US 7,643,348 B2 *Jan. 5, 2010
(54) PREDICTIVE PROGRAMMING IN NON-VOLATILE MEMORY
(75) Inventor: Raul-Adrian Cernea, Santa Clara, CA (US)
(73) Assignee: Sandisk Corporation, Milpitas, CA (US)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 79 days.
This patent is subject to a terminal disclaimer.
(21) Appl.No.: 11/733,694
(22) Filed: Apr. 10, 2007
(65) Prior Publication Data
US 2008/0253197 Al Oct. 16, 2008
(51) Int. CI.
(52) U.S. CI 365/185.24; 365/185.17;
(58) Field of Classification Search 365/185 .24,
365/185.17, 185.18, 185.19, 185.28, 185.03 See application file for complete search history.
(56) References Cited
U.S. PATENT DOCUMENTS
In a nonvolatile memory having an array of memory cells, wherein the memory cells are individually programmable to one of a range of threshold voltage levels, there is provided a predictive programming mode in which a predetermined function predicts what programming voltage level needs to be applied in order to program a given memory cell to a given target threshold voltage level. In this way, no verify operation needs to be performed, thereby greatly improving the performance of the programming operation. In a preferred embodiment, the predetermined function is linear and is calibrated for each memory cell under programming by one or more checkpoints. The checkpoint is an actual programming voltage that programs the memory cell in question to a verified designated threshold voltage level.
16 Claims, 16 Drawing Sheets