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:
Jan. 26, 2010
Filed:
Apr. 08, 2005
Brian Tyrrell, Nashua, NH (US);
Michael Fritze, Acton, MA (US);
Brian Tyrrell, Nashua, NH (US);
Michael Fritze, Acton, MA (US);
Massachusetts Institute of Technology, Cambridge, MA (US);
Abstract
A method forms patterns on a substrate by exposing the substrate a first time and exposing the substrate a second time using a mask containing gray-tone features. The gray-tone features locally adjust an exposure dose in regions corresponding to features defined in the primary exposure. Moreover, the gray-tone features enable the forming of features having different critical dimensions on a substrate. The gray-tone features may be implemented as sub-resolution features formed by pixellation. The gray-tone features may also be realized by the local size bias of trim features on the trim mask that have dimensions near the resolution limit of the exposure system. The trim mask containing gray-tone features may have regions with different transmissivities or generate varying illumination intensities.