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:
Jul. 12, 2005
Filed:
Apr. 26, 2002
Tomoharu Fujiwara, Ageo, JP;
Kazuaki Suzuki, Tokyo, JP;
Tomoharu Fujiwara, Ageo, JP;
Kazuaki Suzuki, Tokyo, JP;
Nikon Corporation, Tokyo, JP;
Abstract
Methods and devices are disclosed for controlling blur resulting from the space-charge effect and geometrical aberration in a charged-particle-beam microlithography apparatus. Based on the pattern-element densities of the exposure units to be transferred to the substrate, a relationship between the total blur and the beam semi-angle, the current density, and/or the beam-acceleration voltage is determined. An optimal beam semi-angle, current density, and/or beam-acceleration voltage is calculated to: (1) minimize the blur during the transfer-exposure of an exposure unit having a certain pattern-element density; (2) make the blur constant during the transfer-exposure of a group of exposure units having various pattern-element densities; or (3) maximize the patterned-beam current during the transfer-exposure of an exposure unit having a certain pattern-element density and blur tolerance. The beam semi-angle, current density, and/or acceleration voltage of the CPB-optical system is then adjusted to the calculated value.