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. 03, 1999
Filed:
Feb. 24, 1998
Richard A Ferguson, Pleasant Valley, NY (US);
Lars W Liebmann, Poughquag, NY (US);
Scott M Mansfield, Hopewell Junction, NY (US);
David S O'Grady, Jericho, VT (US);
Alfred K Wong, Beacon, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A two-step method for eliminating transmission errors in alternating phase-shifting masks is described. Initially, the design data is selectively biased to provide a coarse reduction in the inherent transmission error between features of different phase, size, shape, and/or location. During fabrication of the mask with the modified data, residual transmission errors are then eliminated via the positioning of the edges of the etched-quartz trenches which define the phase of a given feature to a set location beneath the opaque chrome film. Application of feedback, in which the aerial image of the mask is monitored during the positioning of the etched-quartz edges, provides additional and precise control of the residual transmission error.