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. 11, 2000
Filed:
Feb. 24, 1999
Advantest Corporation, Tokyo, JP;
Abstract
Disclosed is a method of producing a block mask, which is employed in an electron-beam lithography apparatus, with high precision irrespective of the size of openings. The electron-beam lithography apparatus is of a type that produces a unit pattern at a time by transmitting an electron beam through openings selected from among a plurality of kinds of openings of a block mask, links the unit pattern with a previous one, and repeats this process to delineate a desired pattern. The method consists of four steps. At the first step, a resist is applied to the surface of a substrate of a block mask. At the next step, the resist is exposed to delineate patterns of a plurality of kinds of openings. At the next step, the exposed resist is developed. At the next step, the substrate of the block mask is etched. Herein, at the step of exposing the resist to delineate the patterns of a plurality of kinds of openings, for exposing the resist to delineate a pattern of openings that are larger than a predetermined size, the perimeters of corresponding opening portions of the resist are exposed by a predetermined width. However, the insides of the corresponding opening portions remain unexposed. Once etching is completed, the perimeter of each large opening portion becomes a penetrating hole. The inside thereof is detached from the substrate of the block mask. A larger hole is thus realized. Consequently, even when the etching is carried out under the same conditions for etching performed to create small openings, large openings can be created with high precision.