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:
Oct. 02, 2007
Filed:
Dec. 08, 2005
Chung-zen Chen, Hsinchu, TW;
Chung-shan Kuo, Shulin, TW;
Chung-Zen Chen, Hsinchu, TW;
Chung-Shan Kuo, Shulin, TW;
Elite Semiconductor Memory Technology, Inc., Hsinchu, TW;
Abstract
An erase method used in an array of flash memory cells arranged in a plurality of sectors provides each sector with an erase flag. The erase flag of sectors to be erased are set to a first value. The memory cells are sequentially verified from a first sector to a last sector whose flag is set to the first value and for each sector from a first address to a last address. When verification fails and the number of the same-cell-verifications is less than a predetermined number, the method applies an erase pulse and verifies the memory call at the same memory address again. When verification fails and the number of same-cell-verifications reaches the predetermined number, the remaining sectors whose flag is set to the first value are verified. When each memory cell of a sector to be erased passes verification, the erase flag of the sector is set to a second value. When the flag of each sector to be erased is set to the second value, the erase operation is terminated.