The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 10, 2002
Filed:
Apr. 12, 2001
Akiko Harasaki, Kawasaki, JP;
Joanna Schmit, Tucson, AZ (US);
Veeco Instruments Inc., Tucson, AZ (US);
Abstract
Bat wings are removed at step discontinuities within the coherence length of the light source of a vertical-scanning interferometer. A first height profile is obtained from a correlogram using a coherence-sensing technique. A second height profile is obtained from phase measurements at the best-focus frame position of the scanner. The two profiles are compared, and phase ambiguities are removed in conventional manner. In addition, during unwrapping the differences in height between two adjacent pixels obtained both by coherence sensing and by phase measurements are compared to f&lgr;/4. Where the inter-pixel height difference calculated by coherence sensing is smaller and the inter-pixel height difference calculated by phase is larger than f&lgr;/4, the phase measurement is corrected by 2&pgr; increments until both coherence and phase inter-pixel height differences are within f&lgr;/4. This additional step removes bat-wing effects from profiles obtained by phase measurement.