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US 5,691,802 AGranted
Catadioptric optical system and exposure apparatus having the same
AssigneeNikon Corporation
InventorTomowaki Takahashi
Life of this patent
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AssigneeNikon Corporation
InventorTomowaki Takahashi
Estimating the term…
It is an object of the invention to provide a catadioptric optical system with an arrangement for realizing a large numerical aperture and reducing the diameter of a concave mirror while ensuring a sufficient working distance on the image side, and also an exposure apparatus using this catadioptric optical system. A catadioptric optical system according to the invention includes a first imaging optical system for forming an intermediate image of a pattern on a first plane, a second imaging optical system for forming a reduced image of the intermediate image on a second plane, and an optical path deflecting member for guiding a light beam from the first imaging optical system to the second imaging optical system. The first imaging optical system has at least a first optical element group having a positive refracting power, and a second optical element group having a concave mirror and a meniscus lens component with a concave surface facing the first imaging optical system. In particular, the first optical element group having a positive refracting power is arranged to guide a light beam from the first plane to the second optical element group.
A catadioptric optical system for forming an image of a pattern on a first plane on a second plane, comprising:
An exposure apparatus comprising:
Dependencies are inferred from the claim text.
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No related US applications are recorded in the indexed filing history.
Catadioptric systems: specially adapted for the UV
Systems with reflecting surfaces, with or without refracting elements: catadioptric systems
Mask projection systems: optical aspects of catadioptric systems, i.e. comprising reflective and refractive elements
Mask projection systems: multiple projection paths, e.g. array of projection systems, microlens projection systems or tandem projection systems
Term ended 3 Nov 2015 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
1. Field of the Invention
The present invention relates to a projection optical system in a projection exposure apparatus such as a stepper used to manufacture semiconductor elements or liquid crystal display elements by photolithography and, more particularly, to a catadioptric projection optical system using a reflection system as an element of an optical system.
2. Related Background Art
FIG. 1 is a view showing the arrangement of a one-shot exposure apparatus to which a catadioptric optical system according to the present invention can be applied;
FIG. 2 is a view showing the arrangement of a scanning exposure apparatus to which the catadioptric optical system according to the present invention can be applied;
FIG. 3 is a view schematically showing the basic arrangement of the catadioptric optical system according to the present invention;
Embodiments of a catadioptric optical system according to the present invention will be described below with reference to FIGS. 1 to 36. This catadioptric optical system can be applied to both a one-shot exposure apparatus and a scanning exposure apparatus.
FIG. 1 is a view showing the arrangement of an apparatus using a one-shot exposure method. Referring to FIG. 1, the exposure apparatus comprises a movable wafer stage 3 (first stage) capable of holding a photosensitive substrate W on its major surface 3a, a movable reticle stage 2 (second stage) for holding a reticle R, a light source 100 for irradiating an exposure light beam having a predetermined wavelength, and an illumination optical system 1 for irradiating the exposure light beam from the light source 100 onto the reticle R and transferring a predetermined pattern of an electronic circuit or the like on the reticle onto the substrate W. The photosensitive substrate W is formed of a substrate 7 such as a silicon wafer or a glass plate having a surface coated with a photosensitive material 8 such as a photoresist. The illumination optical system 1 has an alignment optical system 110 for aligning the reticle R and the photosensitive substrate W.
The exposure apparatus also has a reticle exchange system 200 for exchanging the reticle R held on the reticle stage 2 or moving the reticle stage 2 in accordance with an instruction from a main control section 400, and a stage control system 300 for moving the wafer stage 3 in accordance with an instruction from the main control section. When alignment of the reticle R and the photosensitive substrate W is to be performed, the main control section 400 obtains the displacement amounts of the stages 2 and 3 from the alignment optical system 110, calculates the moving amounts of the stages 2 and 3, and outputs moving instructions to the stages 2 and 3. The stages 2 and 3 are moved in predetermined directions in accordance with the moving instructions and moving amounts from the main control section 400, thereby adjusting the relative position between the reticle R and the photosensitive substrate W.