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:
Jun. 02, 2015
Filed:
May. 19, 2008
Allen H. Gabor, Katonah, NY (US);
Wai-kin LI, Beacon, NY (US);
Allen H. Gabor, Katonah, NY (US);
Wai-Kin Li, Beacon, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method and apparatus are provided for improving the focusing of a substrate such as a wafer during the photolithography imaging procedure of a semiconductor manufacturing process. The invention is particularly useful for step-and-scan system and the CD of two features in each exposure field are measured in fields exposed at varying focus to form at least two Bossung curves. Exposure focus instructions are calculated based on the intersection point of the curves and the wafer is then scanned and imaged based on the calculated exposure focus instructions. In another aspect of the invention, when multiple wafers are being processed operational variances may cause a drift in the focus. The focus drift can be easily corrected by measuring the critical dimension of each of the features and comparing the difference to determine if any focus offset is needed to return the focus to the original calculated focus value.