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:
Jun. 02, 1998
Filed:
Jan. 16, 1996
Hiroshi Nozue, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
The aperture structure is for cell projection writing of patterns on a semiconductor substrate by an electron beam. The aperture structure includes a wafer, and a plurality of aperture patterns formed in the wafer. The aperture patterns are positioned and structured such that a thermal coefficient of a front side of the wafer and that of a back side of the wafer are the same as each other. The aperture patterns are positioned in a central portion and are symmetrically shaped in the depth direction of the base. For fabricating the aperture structure, the front side of the wafer is etched, or the front side and the back side of the wafer are etched, and the aperture patterns are formed in the etched portion or portions. The back side of the wafer is etched to the same depth as the front side. The aperture structure does not become warped, and the accuracy of generating patterns on a wafer with electron beams is greatly enhanced.