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US 7,606,077 B2Granted
Non-volatile memory with reduced erase/write cycling during trimming of initial programming voltage
AssigneeSanDisk Corporation
InventorsYan Li, Loc Tu, Charles Moana Hook
Life of this patent
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Abstract
High performance non-volatile memory devices have the programming voltages trimmed for individual types of memory pages and word lines. A group of word lines within each erasable block of memory are tested successive program loops to minimize the problem of incurring excessive number of erase/program cycles. An optimum programming voltage for a given type of memory pages is derived from statistical results of a sample of similar of memory pages.
Claims20
A non-volatile memory comprising:
- an array of memory cells that is organized into erasable blocks, each erasable block containing a block of word lines for accessing memory cells that are erasable together, and each word line containing at least one page of memory cells that are programmable together;
- a designated sample of pages representative of the given page within a block;
- an associated programming voltage for programming each page of the sample, the associated programming voltage having a staircase waveform with an associated initial value and a predetermined number of steps;
- a built-in self testing module for determining the associated initial value for a given page, said module providing memory operations including:
- (a) erasing the block containing the sample of pages;
- (b) determining for every page in the sample if the page is programmed to a target pattern using the associated programming voltage with the associated initial value;
- and if programmed, excluding the page from further processing after accumulating the associated initial value as part of a gathered statistics, otherwise, incrementing the associated initial value by a predetermined step;
- (c) repeating (a) to (b) until each of the sample of pages has either been program-verified or been programmed with the associated programming voltage incremented to a predetermined maximum voltage;
- and
- (d) providing the gathered statistic for computing an average initial value for the sample and for deriving a starting programming voltage for the page based on the average initial value of the sample.
7 more elements
Dependencies are inferred from the claim text.