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. 31, 2004
Filed:
Oct. 29, 2002
Michael Edward Scaman, Goshen, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
An apparatus and method for detection of electromechanical and mechanical errors in an electron beam device is provided. First the existing subfield is divided into a gridlike structure where each grid can be considered a target. Then a plurality of target points are provided on each grid for measuring combined directional variances. The separated horizontal and vertical variances is also measured for each of the target points. This leads to the performance of a significance tests, based on the F statistic which we refer to as F , for horizontal and vertical values of each target points during which F values are also obtained. The F values are then compared for horizontal and vertical values and an error alert provided when there is a sufficiently large disparity between the separated F values. In an alternate embodiment of the present invention, a three dimensional grid is also provided to be used in a similar manner. The severity of the error can also be determined based on the disparity of the values. Lastly we refer to a simple F statistic for testing for flatness of the entire field, based on row and field information and refer to it as F .