Loading patent…
AssigneeKLA-Tencor Corporation
InventorsDavid R. Shafer, Young-Ho Chuang, J. Joseph Armstrong
Estimating the term…
A design for inspecting specimens, such as photomasks, for unwanted particles and features such as pattern defects is provided. The system provides no central obscuration, an external pupil for aperturing and Fourier filtering, and relatively relaxed manufacturing tolerances, and is suited for both broad-band bright-field and laser dark field imaging and inspection at wavelengths below 365 nm. In many instances, the lenses used may be fashioned or fabricated using a single material. Multiple embodiments of the objective lensing arrangement are disclosed, all including at least one small fold mirror and a Mangin mirror. The system is implemented off axis such that the returning second image is displaced laterally from the first image so that the lateral separation permits optical receipt and manipulation of each image separately. The objective designs presented have the optical axis of the Mangin mirror image relay at ninety degrees to the optical axis defined by the focusing lenses, or an in-line or straight objective having one ninety degree bend of light rays.
A combined catadioptric lensing and mirror optical inspection system comprising:
A method for inspecting a specimen, comprising the steps of:
An objective for inspecting a specimen, comprising:
An apparatus for inspecting a specimen, comprising:
An apparaus for imaging a specimen comprising:
A catadioptric imaging system for inspecting a specimen comprising:
An unobscured catadioptric objective comprising:
An unobscured catadioptric objective comprising:
Dependencies are inferred from the claim text.