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:
Mar. 02, 2010
Filed:
Apr. 28, 2004
Adlai H. Smith, Escondido, CA (US);
Robert O. Hunter, Jr., San Diego, CA (US);
Adlai H. Smith, Escondido, CA (US);
Robert O. Hunter, Jr., San Diego, CA (US);
Litel Instruments, San Diego, CA (US);
Abstract
A technique for the determination of dynamic lens field curvature uniquely associated with a photolithographic scanner is described. A series of lithographic exposures is performed on a resist coated silicon wafer using a photolithographic scanner. The lithographic exposures produce an array of focusing fiducials that are displaced relative to each other in a unique way. The resulting measurements are fed into a computer algorithm that determines the dynamic lens field curvature (ZDLC) perpendicular to the scanning direction in an absolute sense. Furthermore, the effects of wafer flatness, wafer surface non-uniformity, and stage error are considered. The ZDLC information can be used to improve lithographic modeling, overlay modeling, and advanced process control techniques related to scanner stage dynamics.