External beam delivery system for laser dark-field illumination in a catadioptric optical system
AssigneeKLA-Tencor Corporation
InventorJ. Joseph Armstrong
Life of this patent
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Abstract
A catadioptric objective configured to inspect a specimen is provided. The catadioptric objective includes a Mangin element having one surface at a first axial location and an extension element positioned together with the Mangin element. The extension element provides a second surface at a second axial location. Certain light energy reflected from the specimen passes to the second surface of the extension element, the Mangin element, and through a plurality of lenses. An aspheric surface may be provided, and light energy may be provided to the specimen using diverting elements such as prisms or reflective surfaces.
Claims25
A catadioptric objective configured to inspect a specimen, comprising:
- a plurality of lenses;
- a Mangin element comprising one surface at a first axial location;
- and
- an extension element positioned together with the Mangin element, wherein the extension element provides a second surface at a second axial location;
- wherein light energy reflected from the specimen passes to the second surface of the extension element, the Mangin element, and through the plurality of lenses.
A specimen inspection apparatus, comprising:
- a light energy source;
- at least one lens;
- and
- a composite Mangin element comprising a first surface axially positioned away from the specimen and a second surface axially positioned toward the specimen and an extension comprising a third surface axially positioned closer to the specimen than the second surface;
- wherein the light energy source is configured to transmit light energy substantially parallel to a surface of the specimen, and the apparatus is further configured to divert light energy around the extension of the composite Mangin element, thereby striking the surface of the specimen, and further wherein certain light energy reflected from the specimen passes through the third surface, second surface, first surface, and at least one lens.
A method for inspecting a specimen, comprising:
- providing a beam of light energy at an angle substantially parallel to a surface of the specimen through a gap bounded by the specimen and a composite Mangin element;
- diverting the beam of light energy toward the surface of the specimen such that certain light energy reflects from the specimen;
- and
- receiving certain light energy reflected from the specimen through the composite Mangin element and at least one lens;
- wherein the composite Mangin element comprises a first axially positioned surface, a second axially positioned surface, and a third axially positioned surface located on a composite Mangin element extension.
An objective for inspecting a specimen, comprising:
- a plurality of lenses;
- a Mangin element comprising a first surface at a first axial position and a second surface at a second axial position;
- and
- an extension located proximate the Mangin element and positioned between the Mangin element and the specimen, the extension providing a third surface at a third axial position;
- wherein certain light energy reflected from the specimen passes through the third surface, the second surface, the first surface, and the plurality of lenses.
Dependencies are inferred from the claim text.