Systems for erasing non-volatile memory using individual verification and additional erasing of subsets of memory cells
First Claim
1. A non-volatile memory system, comprising:
- a set of non-volatile storage elements, said set includes a first subset and a second subset of non-volatile storage elements; and
managing circuitry in communication with said set of non-volatile storage elements, said managing circuitry erases said set by;
enabling erasing of said first and said second subset of non-volatile storage elements, applying one or more erase voltage pulses to said set while said first and second subset are enabled for erasing until said first subset is verified as erased, after said first subset is verified as erased, inhibiting said first subset from further erasing while enabling erasing of said second subset, and applying one or more additional erase voltage pulses to said set while said first subset is inhibited and said second subset in enabled until said second subset is verified as erased.
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Accused Products
Abstract
A set of non-volatile storage elements is divided into subsets for erasing in order to avoid over-erasing faster erasing storage elements. The entire set of elements is erased until a first subset of the set of elements is verified as erased. The first subset can include the faster erasing cells. Verifying the first subset includes excluding a second subset from verification. After the first subset is verified as erased, they are inhibited from erasing while the second subset is further erased. The set of elements is verified as erased when the second subset is verified as erased. Verifying that the set of elements is erased can include excluding the first subset from verification or verifying both the first and second subsets together. Different step sizes are used, depending on which subset is being erased and verified in order to more efficiently and accurately erase the set of elements.
112 Citations
28 Claims
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1. A non-volatile memory system, comprising:
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a set of non-volatile storage elements, said set includes a first subset and a second subset of non-volatile storage elements; and
managing circuitry in communication with said set of non-volatile storage elements, said managing circuitry erases said set by;
enabling erasing of said first and said second subset of non-volatile storage elements, applying one or more erase voltage pulses to said set while said first and second subset are enabled for erasing until said first subset is verified as erased, after said first subset is verified as erased, inhibiting said first subset from further erasing while enabling erasing of said second subset, and applying one or more additional erase voltage pulses to said set while said first subset is inhibited and said second subset in enabled until said second subset is verified as erased. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A non-volatile memory system, comprising:
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a set of non-volatile storage elements, said set includes a first subset and a second subset of non-volatile storage elements; and
managing circuitry in communication with said set of non-volatile storage elements, said managing circuitry erases said set by applying an erase voltage to said set while each non-volatile storage element in said set is enabled for erase and verifying whether said first subset is erased while excluding said second subset from verification, said managing circuitry repeats said applying and verifying until said first subset is verified as erased, said managing circuitry inhibits erasing of said first subset and enables erasing of said second subset after said first subset is verified as erased and applies an erase voltage to said set while said second subset is enabled for erase and said first subset is inhibited from erase, said managing circuitry verifies whether said set of non-volatile storage elements is erased by verifying whether said second subset is erased. - View Dependent Claims (19, 20, 21, 22, 23, 24)
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25. A non-volatile memory system, comprising:
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a set of non-volatile storage elements, said set includes a first subset and a second subset of non-volatile storage elements; and
managing circuitry in communication with said set of non-volatile storage elements, said managing circuitry receives a request to erase said set of non-volatile storage elements, said managing circuitry erases said set in response to said request by;
applying an erase voltage to said set while enabling erasure of each non-volatile storage element of the set, verifying whether said first subset of non-volatile storage elements is erased, repeating said applying and verifying until said first subset is verified as erased, inhibiting erasing of said first subset of non-volatile storage elements subsequent to said repeating, applying an erase voltage to said set while said first subset is inhibited in order to further erase said second subset, and verifying whether said set of elements is erased by verifying whether said second subset of elements is erased. - View Dependent Claims (26, 27, 28)
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Specification