# US 11,443,811 B2 · Data erase operations for a memory system

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,443,811 B2
- Document ID: US11443811B2
- Status: Granted
- Kind: B2
- Application number: 17/074,758
- Filed: 2020-10-20
- Published: 2021-02-04
- Granted: 2022-09-13
- Earliest claimed: 2018-05-31
- Assignees: Micron Technology, Inc.
- Applicants: Micron Technology, Inc.
- Inventors: Kevin R. Brandt; Adam J. Hieb; Jonathan Tanguy; Preston A. Thomson
- Web page: https://patentgrep.com/patent/US11443811B2

## CPC

- G11C 16/16: for erasing blocks, e.g. arrays, words, groups
- G11C 7/20: Memory cell initialisation circuits, e.g. when powering up or down, memory clear, latent image memory
- G11C 16/08: Address circuits; Decoders; Word-line control circuits
- G11C: STATIC STORES (semiconductor memory devices H10B)

## Abstract

A data erase operation is performed on the memory system. The directed data erase operation performed on the memory system erases blocks of the memory device including blocks that are indicated as not including user data. In some embodiments, a data erase operation may be performed on a memory system to erase those groups of memory cells (e.g., blocks) indicated as not including user data. In some embodiments, a data erase operation may be performed on a memory system to erase those groups of memory cells (e.g., blocks) indicated as valid without erasing those groups of memory cells (e.g., blocks) indicated as invalid. In some embodiments, a data erase operation that can be performed on a memory system may obtain information associated with failing scenes of groups of memory cells (e.g., blocks) prior to obtaining the information, and erase the blocks (e.g., invalid blocks) subsequently.

## Claims

### Claim 1

An apparatus, comprising:
a memory device including a plurality of blocks; and
a controller coupled to the memory device and configured to:
mark, while a first number of blocks of the plurality of blocks remains as valid, a second number of blocks of the plurality of blocks as invalid in response to respective memory operations performed on the second number of blocks having failed;
receive a data erasure command subsequent to the second number of blocks being marked as invalid;
responsive to receiving the data erasure command, perform a data erase operation on the memory device;
wherein the data erase operation performed on the memory device results in erasure of the number of first blocks marked as valid without erasing, as directed by the data erasure command, the number of second blocks marked as invalid such that information associated with corresponding failing scenes of the number of second blocks are obtainable subsequent to performing the data erase operation.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein the controller is configured to update, prior to perform the data erase operation, a table indicating which blocks of the memory device are invalid.

### Claim 3 (depends on 1)

The apparatus of claim 1, wherein the controller is further coupled to a host and the data erasure command is received to the controller from the host.

### Claim 4 (depends on 1)

The apparatus of claim 1, wherein the memory device comprises a plurality of NAND Flash memory devices in which a physical block is a unit of erasure and is configured to store a plurality of pages of data.

### Claim 5 (depends on 1)

The apparatus of claim 1, wherein the controller is configured to destroy, to perform the data erase operation on the memory device, destroying a readability of the blocks of the number of first blocks by changing information associated with an encryption key of an encryption key corresponding to the data stored in the number of first blocks.

### Claim 6 (depends on 5)

The apparatus of claim 5, wherein the encryption key is stored in one of the number of first blocks.

### Claim 7 (depends on 1)

The apparatus of claim 1, the information associated with corresponding failing scenes of the number of second blocks comprises a raw bit error rate of each one of the number of second blocks.

### Claim 8 (depends on 1)

The apparatus of claim 1, wherein the apparatus is a solid state drive.

### Claim 9 (depends on 1)

The apparatus of claim 1, wherein the controller is configured to:
update, subsequent to the data erase operation, a status of the number of first blocks previously marked as valid to a free status; and
maintain, subsequent to the data erase operation, a status of the number of second blocks as invalid.

### Claim 10

A method, comprising:
receiving a data erasure command from a host;
responsive to receiving the data erasure command, determining that:
a first portion of a memory device that was marked as valid prior to the data erasure command; and
a second portion of the memory device that was marked as invalid prior to the data erasure command and responsive to a corresponding bit error rate (BER) of the second portion of the memory device exceeding a threshold BER; and
performing a data erase operation on the first portion of the memory device;
wherein the first portion of the memory device no longer stores the valid data, while the second portion of the memory device still stores the invalid data as a result of the data erase operation performed as directed by the data erasure command.

### Claim 11 (depends on 10)

The method of claim 10, further comprising transferring, subsequent to the data erase operation, data from the second portion of the memory device to the host.

### Claim 12 (depends on 10)

The method of claim 10, wherein performing the data erase operation on the first portion of the memory device comprises erasing the valid data without erasing the invalid data.

### Claim 13 (depends on 10)

The method of claim 10, wherein performing a data erase operation on the first portion of the memory device comprises destroying a readability of memory cells of the first portion by changing information associated with an encryption key of an encryption key corresponding to the data stored in the first portion.

### Claim 14 (depends on 10)

The method of claim 10, wherein performing a data erase operation on the first portion of the memory device comprises destroying a readability of memory cells of the first portion by overwriting a particular data pattern to only a portion of memory cells of the first portion.

### Claim 15

A system, comprising:
a host; and
a controller coupled to a memory device comprising a plurality of blocks, the plurality of blocks further comprising:
a first portion of the plurality of blocks indicated as valid; and
a second portion of the plurality of blocks that is indicated as invalid responsive to a corresponding bit error rate (BER) of the second portion of the plurality of blocks exceeding a threshold BER;
wherein the host is configured to provide a data erasure command to the controller to cause the controller to:
erase, as directed by the data erasure command, the first portion of the plurality of blocks indicated as valid; and
not to erase, as directed by the data erasure command, the second portion of the plurality of blocks indicated as invalid.

### Claim 16 (depends on 15)

The system of claim 15, wherein:
the host is further configured to cause the controller to retrieve data remaining in the second portion of the plurality of blocks; and
the data remaining in the second portion of the plurality of blocks comprises information associated with corresponding failing scenes of the second portion of the plurality of blocks.

### Claim 17 (depends on 15)

The system of claim 15, wherein the controller is configured to, in response to receipt of the data erasure command from the host, erase the first portion indicated as valid without erasing the second portion indicated as invalid.

### Claim 18 (depends on 15)

The system of claim 15, wherein the host is further configured to provide, along with the data erasure command, a trim command to the controller to cause the controller to update a table that lists statuses of each portion of the plurality of blocks.

### Claim 19 (depends on 15)

The system of claim 15, wherein blocks of the second portion are grown bad blocks (GBB).