Joseph L Carter

US Patent:

58594248, Jan 12, 1999

Filed:

Apr 8, 1997

Appl. No.:

8/835533

Inventors:

Adam E. Norton - Palo Alto CA
Kenneth C. Johnson - Santa Clara CA
Joseph R. Carter - San Jose CA

Assignee:

KLA-Tencor Corporation - San Jose CA

International Classification:

G01J 350

US Classification:

250226

Abstract:

Because of diffraction effects caused by slits or apertures in optical measurement systems, the radiation energy which is directed towards a particular region on a sample will be spread over a larger area than desirable. By employing an apodizing filter in the radiation path in such system, diffraction tails of the system will be reduced. The apodizing filter preferably has a pattern of alternating high transmittance areas and substantially opaque areas where the locally averaged transmittance function is an apodizing function. In the preferred embodiment, the locally averaged transmittance function varies smoothly and monotonically from the periphery to the center of the filter.

Address:

6502 Marina Pointe Vlg Ct APT 204, Tampa, FL 33635

VIN:

KNAFE121675474200

Make:

KIA

Model:

SPECTRA

Year:

2007