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:
Jul. 22, 2003
Filed:
Oct. 09, 2001
Mark McCord, Mountain View, CA (US);
Jun Pei, Campbell, CA (US);
KLA-Tencor Technologies Corp., Milpitas, CA (US);
Abstract
Systems and methods for determining the height of a surface of a specimen, such as a surface of a semiconductor device wafer are provided. A system may be configured to generate a comparison signal that may used to alter a Z-axis fine height adjustment of the system. The system may include for example, a processing tool, a metrology tool, or an inspection tool that may be used in semiconductor device fabrication. In this manner, the system may be configured to maintain a constant working distance between the wafer surface and an optical column of the system. A system may include an off-axis dual beam symmetric height sensor due to mechanical constraints of the system. The dual beam symmetric height sensor may provide automatic focusing of the wafer with high precision by substantially eliminating wafer pattern-induced error in comparison signals generated by the system.