Inventors:
Dieter Wilk - San Jose CA, US
Anlun Tang - Pleasanton CA, US
Eric Vella - Mountain View CA, US
Rex Runyon - Fremont CA, US
Jamie Sullivan - Sunnyvale CA, US
Ralph Johnson - Los Gatos CA, US
Assignee:
KLA-Tencor Technologies Corporation
International Classification:
G01N021/00
Abstract:
Disclosed are mechanisms for selectively filtering spatial portions of light emanating from a sample under inspection within an optical system. In one embodiment, a programmable spatial filter (PSF) is constructed from materials that are compatible with light in a portion of the UV wavelength range. In a specific implementation, the PSF is constructed from a UV compatible material, such as a polymer stabilized liquid crystal material. In a further aspect, the PSF also includes a pair of plates that are formed from a UV grade glass. The PSF may also include a relatively thin first and second ITO layer that results in a sheet resistance between about 100 and about 300 per square. The PSF provides selective filtering in two directions. In other words, the PSF provides two dimensional filtering.