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. 07, 2003
Filed:
Aug. 17, 2001
Kiyokazu Ishige, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
The present invention prevents a charge-up during a wiring layer etching in a nonvolatile semiconductor storage apparatus, having a floating gate and a control gate to which both of positive and negative voltages are applied during a memory cell operation, by providing a current path from the control gate to a substrate via a charge-up preventing element. A first well is formed in the substrate. A second well is formed in the first well. The charge-up preventing element is formed in the second well. The substrate and second well are of one conductive type (p or n) and the first well and charge-up preventing element are of the other conductive type. Before memory cell operation, the control gate is disconnected from the charge-up preventing element.