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:
Aug. 28, 2007
Filed:
Mar. 12, 2004
Adlai H. Smith, Escondido, CA (US);
Joseph Bendik, Escondido, CA (US);
Robert O. Hunter, Jr., San Diego, CA (US);
Adlai H. Smith, Escondido, CA (US);
Joseph Bendik, Escondido, CA (US);
Robert O. Hunter, Jr., San Diego, CA (US);
Litel Instruments, San Diego, CA (US);
Abstract
A process for providing illumination source conditions for the accurate determination Zernike tilt coefficients in the presence of coma is described. Large feature-shift coma sensitivity is simulated for a range of illumination conditions. The resulting source sensitivity data is modeled and a practical array of source shapes, each of which is optimized to eliminate the effects of transverse distortion due to third-order coma, is identified. The optimized set of source shapes can be used to more accurately determine Zernike terms a2 and a3 using a variety of methods. Knowledge of the lens distortion data in the absence of coma induced shifts can be entered into more traditional overlay regression routines to better identify systematic and random error. Additional applications of the above outlined procedure include: improved lithographic simulation using conventional optical modeling software and advanced process control in the form of feedback loops that automatically adjust the projection lens for optimum system performance.