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:
Feb. 06, 2007
Filed:
Dec. 22, 2004
Hedong Yang, Santa Clara, CA (US);
Amir Azordegan, Santa Clara, CA (US);
Hedong Yang, Santa Clara, CA (US);
Amir Azordegan, Santa Clara, CA (US);
KLA-Tencor Technologies Corporation, Milpitas, CA (US);
Abstract
One embodiment disclosed relates to an automated process for focusing a charged-particle beam in an apparatus onto an area of a substrate. A focusing parameter of the apparatus is set to a value, and intensity data is acquired from the area. The foregoing setting and acquiring steps are repeated for a range of values for the focusing parameter. A focusing sharpness measure is computed for each value of the focusing parameter based on noise in the acquired intensity data, and an in-focus value is determined for the focusing parameter based on the computed focusing sharpness measures. The focusing parameter of the apparatus may be, for example, an objective lens current, or a substrate bias voltage. The computation of the noise-based focusing sharpness measure may involve generating shifted or interleaved signals and calculating correlations between these signals. The focusing may be advantageously performed on an area lacking substantial edge information.