Illuminating optical system
AssigneeCanon Kabushiki Kaisha
InventorsMasakatu Ota, Takashi Omata
Life of this patent
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Abstract
This specification discloses an illuminating optical system in which the optical position of a multi-beam generating optical element along the direction of the optical axis is variable, whereby a desired printing wavelength selected from a wide wavelength range from the UV area to the Deep UV area can be used in the same illuminating optical system and illumination irregularity can be kept very slight.
Claims18
An illuminating optical system for illuminating an object, said optical system comprising:
- light source means for selectively producing light having a desired wavelength;
- a multi-beam generating optical element for receiving the light having a desired wavelength produced by said light source means, and for forming a plurality of light sources that emit light as multiple beams;
- a stationary collimator lens for directing the multiple beams emitted from said multi-beam generating optical element to the object;
- and
- means for changing an optical path between said plurality of light sources and said stationary collimator lens so as to coincide the position of said plurality of light sources with a focus position of said collimator lens.
An illuminating optical system for illuminating a mask to transfer a pattern thereon to a wafer, comprising:
- light providing means for providing light;
- wavelength changing means for changing the wavelength of light provided by said light providing means;
- multi-beam forming means for forming multiple beams utilizing light provided by said light providing means;
- optical means for illuminating the mask with light from the multiple beams formed by said multi-beam forming means to transfer the pattern on the mask to the wafer;
- and
- position changing means for changing a position of said multi-beam forming means relative to said optical means in accordance with the wavelength of the light provided by said light providing means as determined by said wavelength changing means, so as to minimize the illumination distribution on the mask.
An illuminating optical system for illuminating a mask for transferring a pattern thereon to a wafer, comprising:
- light providing means for providing light;
- wavelength changing means for changing the wavelength of the light provided by said light providing means;
- multi-beam forming means for forming multiple beams utilizing light provided by said light providing means;
- optical means for illuminating the mask with light from the multiple beams formed by said multi-beam forming means to transfer the pattern on the mask to the wafer;
- and
- position changing means for changing the position of said multi-beam forming means relative to said optical means in accordance with the wavelength of the light provided by said light providing means as determined by said wavelength changing means, so as to maintain the angle of inclination of principal rays of said multiple beams directed to the mask substantially the same.
An illuminating optical system for illuminating a mask to transfer a pattern thereon to a wafer, comprising:
- means for providing light having a desired wavelength;
- optical means for illuminating the mask with light provided by said light providing means to transfer the pattern on the mask to the wafer;
- and
- controlling means for maintaining constant the angle of inclination of a principal ray of the light directed to the mask when the wavelength of the light provided by said providing means changes.
An illuminating optical system for illuminating a mask for transferring a pattern thereon to a wafer, comprising:
- light source means for providing light having a desired wavelength;
- optical means for illuminating the mask with light provided by said light source means to transfer the pattern on the mask to the wafer;
- and
- means for minimizing the change of the illumination distribution on the mask when the wavelength of light provided by said light source means changes.
Dependencies are inferred from the claim text.