# US 12,216,915 B2 · Adaptive read disturb scan

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- Number: US 12,216,915 B2
- Document ID: US12216915B2
- Status: Granted
- Kind: B2
- Application number: 17/967,265
- Filed: 2022-10-17
- Published: 2024-04-18
- Granted: 2025-02-04
- Earliest claimed: 2022-10-17
- Assignees: Micron Technology, Inc.
- Applicants: Micron Technology, Inc.
- Inventors: Animesh R. Chowdhury; Kishore K. Muchherla; Nicola Ciocchini; Akira Goda; Jung Sheng Hoei; Niccolo′ Righetti; Jonathan S. Parry
- Web page: https://patentgrep.com/patent/US12216915B2

## CPC

- G06F 3/0619: {in relation to data integrity, e.g. data losses, bit errors}
- G06F 3/061: {Improving I/O performance}
- G06F 3/0653: {Monitoring storage devices or systems}
- G06F 3/0659: {Command handling arrangements, e.g. command buffers, queues, command scheduling}
- G06F 3/0679: {Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]}
- G11C 16/26: Sensing or reading circuits; Data output circuits
- G11C 29/08: Functional testing, e.g. testing during refresh, power-on self testing [POST] or distributed testing
- G11C 29/52: Protection of memory contents; Detection of errors in memory contents
- G11C 16/32: Timing circuits
- G11C 16/3418: {Disturbance prevention or evaluation; Refreshing of disturbed memory data}
- G11C 16/349: {Arrangements for evaluating degradation, retention or wearout, e.g. by counting erase cycles}
- G11C 29/10: Test algorithms, e.g. memory scan [MScan] algorithms; Test patterns, e.g. checkerboard patterns
- G11C 29/4401: {for self repair}
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- G11C: STATIC STORES (semiconductor memory devices H10B)

## Abstract

Apparatuses, systems, and methods for adapting a read disturb scan. One example method can include determining a delay between a first read command and a second read command, incrementing a read count based on the determined delay between the first read command and the second read command, and adapting a read disturb scan rate based on the incremented read count.

## Claims

### Claim 1

A method, comprising:
determining a delay between a first read command and a second read command;
incrementing a read count based on the determined delay between the first read command and the second read command; and
adapting a read disturb scan rate based on the incremented read count.

### Claim 2 (depends on 1)

The method of claim 1, further comprising determining the delay between the first read command and the second read command based on a command queue depth.

### Claim 3 (depends on 2)

The method of claim 2, further comprising determining the command queue depth based on a transfer size.

### Claim 4 (depends on 3)

The method of claim 3, further comprising determining the transfer size based on a number of physical addresses associated with a number of commands in the command queue.

### Claim 5 (depends on 2)

The method of claim 2, further comprising determining the command queue depth based on a number of sequential read commands.

### Claim 6 (depends on 5)

The method of claim 5, further comprising determining the number of sequential read commands based on a physical address of the first read command and a physical address of the second read command.

### Claim 7 (depends on 1)

The method of claim 1, further comprising determining the delay between the first read command and the second read command based on a look-ahead read.

### Claim 8 (depends on 7)

The method of claim 7, further comprising performing the look-ahead read based on sequential pattern detection.

### Claim 9

An apparatus, comprising:
a memory; and
a processor configured to:
receive a number of read commands;
increment a read count by a first value in response to determining a first read command of the number of read commands in a block address is succeeded by a second read command of the number of read commands in the block address within a particular period of time;
increment the read count by a second value in response to determining the first read command in the block address is succeeded by the second read command in the block address after the particular period of time; and
increment the read count by a third value in response to determining the first read command in the block address is succeeded by a program command in the block address within the particular period of time.

### Claim 10 (depends on 9)

The apparatus of claim 9, wherein the first value is less than the second value.

### Claim 11 (depends on 9)

The apparatus of claim 9, wherein the third value is less than the second value.

### Claim 12 (depends on 9)

The apparatus of claim 9, wherein the processor is further configured to initiate a read disturb scan in response to the incremented read count reaching a threshold.

### Claim 13 (depends on 9)

The apparatus of claim 9, further comprising a read counter configured to record the read count.

### Claim 14

A system, comprising:
a host; and
a memory coupled to the host, wherein the memory comprises:
an array of memory cells; and
a processor coupled to the array of memory cells, wherein the processor is configured to:
increment a read count by a first value in response to receiving a number of sequential read commands from the host;
increment the read count by a second value in response to receiving a random read command from the host; and
initiate a read disturb scan in response to the incremented read count reaching a threshold.

### Claim 15 (depends on 14)

The system of claim 14, wherein the host is configured to transmit a first command to the memory including the number of sequential read commands.

### Claim 16 (depends on 15)

The system of claim 15, wherein the number of sequential read commands are for a first file.

### Claim 17 (depends on 16)

The system of claim 16, wherein the first file is a media file.

### Claim 18 (depends on 15)

The system of claim 15, wherein the host is configured to transmit a second command to the memory including the random read command.

### Claim 19 (depends on 18)

The system of claim 18, wherein the random read command is for a second file, wherein a size of the second file is less than a size of the first file.