# US 12,001,686 B2 · Apparatus with post-manufacturing data update mechanism and methods for operating the same

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- Number: US 12,001,686 B2
- Document ID: US12001686B2
- Status: Granted
- Kind: B2
- Application number: 17/865,203
- Filed: 2022-07-14
- Published: 2024-01-18
- Granted: 2024-06-04
- Earliest claimed: 2022-07-14
- Assignees: Micron Technology, Inc.
- Applicants: Micron Technology, Inc.
- Inventors: William C. Filipiak; Elancheren Durai; Quincy R. Holton; Adam Satar; Brett Hunter; David R. Silwanowicz
- Web page: https://patentgrep.com/patent/US12001686B2

## CPC

- G06F 3/0634: {by changing the state or mode of one or more devices}
- G06F 3/0619: {in relation to data integrity, e.g. data losses, bit errors}
- G06F 3/0679: {Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]}
- G11C 7/04: with means for avoiding disturbances due to temperature effects
- G11C 11/40626: {Temperature related aspects of refresh operations}
- G11C 16/26: Sensing or reading circuits; Data output circuits
- G11C 16/3418: {Disturbance prevention or evaluation; Refreshing of disturbed memory data}
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- G11C: STATIC STORES (semiconductor memory devices H10B)

## Abstract

Methods, apparatuses and systems related to managing deck-specific read levels are described. The apparatus may include a memory array having the memory cells organized into two or more decks. The apparatus can determine a delay between programming the decks. The apparatus can derive and implement the deck-specific read levels by selectively adjusting a base read level with an offset level according to the delay and/or the targeted read location.

## Claims

### Claim 1

A memory device, comprising:
a memory array including rewritable memory cells configured to store initial levels of charges representative of preloaded data prior to an environmental stimulus; and
a memory controller operably coupled to the memory array and configured to—
dynamically generate a shift measure based on scanning the rewritable memory cells using a scan-read position,
wherein the shift measure represents one or more changes in the initial levels of the stored charges caused by the environmental stimulus,
wherein the scanning level is a threshold voltage that is offset by a scanning offset from an initial read position predetermined for reading the preloaded data; and
implement a preload adjustment mechanism based on the dynamically generated shift measure, wherein the preload adjustment mechanism is configured to address the one or more changes in the initial levels and maintain accessibility for the preloaded data, wherein the preload adjustment mechanism is configured to selectively generate a post-deployment message for notifying a user that the preloaded data requires refreshing after the environmental stimulus.

### Claim 2 (depends on 1)

The memory device of claim 1, wherein:
the environmental stimulus corresponds to increased temperatures associated with a reflow process that occurs after the preloading the data;
the shift measure represents an estimate of charge loss caused by the increased temperatures during the reflow process; and
the scan-read position is offset from the initial read position corresponding to a floor threshold for a corresponding bit level.

### Claim 3 (depends on 1)

The memory device of claim 1, wherein the memory controller is further configured to:
based on the shift measure, determine that the rewritable memory cells have altered data stored therein, wherein the altered data corresponds to the preloaded data that has been corrupted due to the one or more changes in the initial levels of stored charges; and
implement the preload adjustment mechanism by selectively generating a post-deployment message for notifying the user that the preloaded data has been corrupted by the environmental stimulus.

### Claim 4 (depends on 3)

The memory device of claim 3, wherein the memory controller is further configured to provide a manual refresh trigger that allows the user to selectively initiate a refresh operation according to a real-time condition of the preloaded data, wherein the refresh operation is configured to restore the stored charges to the initial levels and change the altered data stored in the memory array back to the preloaded data.

### Claim 5 (depends on 1)

The memory device of claim 1, wherein the memory controller is further configured to:
periodically trigger a refresh operation during post-deployment operation of the memory device, wherein the refresh operation is configured to refresh charges stored in the memory array; and
wherein the preload adjustment mechanism is configured to selectively adjust a first trigger for the periodic refresh operation instead of or in addition to generating the post-deployment message.

### Claim 6 (depends on 5)

The memory device of claim 5, wherein selectively adjusting the first trigger includes reducing a delay until the first trigger to reduce or reverse the one or more changes in the initial levels.

### Claim 7 (depends on 5)

The memory device of claim 5, wherein the memory controller is configured to:
periodically trigger the refresh operation based on—
tracking an operation count representative of a number of performed memory access and/or activation operations;
triggering the refresh operation when the operation count reaches a predetermined threshold; and
resetting the operation count based on triggering the refresh operation; and
implement the preload adjustment mechanism by loading a scheduling adjustment to the operation count when (1) the user bypasses a manual refresh and/or (2) the shift measure is a refresh adjustment threshold and a notice threshold, wherein the scheduling adjustment is a positive number.

### Claim 8 (depends on 7)

The memory device of claim 7, wherein the scheduling adjustment corresponds to a fixed integer value.

### Claim 9 (depends on 7)

The memory device of claim 7, wherein the memory controller is further configured to dynamically compute the scheduling adjustment according to the shift measure.

### Claim 10 (depends on 5)

The memory device of claim 5, wherein the memory controller is further configured to implement the preload adjustment mechanism by selecting from a response set that includes:
when the shift measure is within a first range, shortening a delay to an initial trigger for a periodic refresh operation that is configured to occur during deployed operation of the memory device; and
when the shift measure is within a second range, generating a post-deployment message for notifying a user that the preloaded data has been corrupted by the environmental stimulus, wherein the second range represents a greater charge loss than the first range.

### Claim 11 (depends on 1)

The memory device of claim 1, wherein the memory controller is further configured to implement the preload adjustment mechanism by generating an adjusted read position configured for use instead of the initial read position in reading the preloaded data when (1) the user bypasses a manual refresh and/or (2) the shift measure is between a refresh adjustment threshold and a notice threshold.

### Claim 12 (depends on 11)

The memory device of claim 11, wherein the memory controller is configured to generate the adjusted read position by adjusting the initial read position by a fixed offset value.

### Claim 13 (depends on 11)

The memory device of claim 11, wherein the memory controller is configured to generate the adjusted read position by adjusting the initial read position by an offset value that is dynamically computed according to the shift measure.

### Claim 14 (depends on 1)

The memory device of claim 1, wherein the memory device is a NAND Flash device configured for automotive applications.

### Claim 15

A method of assembling a memory device that includes rewritable memory cells, the method comprising:
preloading content on the memory device by establish initial levels of stored charges in the rewritable memory cells;
after preloading the content, attaching the memory device to a substrate by reflowing solder at increased temperatures;
dynamically generating a shift measure based on scanning the rewritable memory cells using a scan-read position,
wherein the shift measure represents one or more changes in the initial levels of the stored charges caused by the increased temperatures,
wherein the scan-read position is a threshold voltage different from an initial read position predetermined for reading the preloaded data; and
dynamically generating a post-deployment message based on the shift measure for notifying a user that the preloaded data has been corrupted by the environmental stimulus.

### Claim 16 (depends on 15)

The method of claim 15, further comprising:
providing a manual refresh trigger that allows the user to selectively initiate a refresh operation for addressing the one or more changes in the initial levels and maintaining accessibility for the preloaded data.

### Claim 17 (depends on 15)

The method of claim 15, further comprising:
increasing an initial value of an operation count representative of a number of performed memory access and/or activation operations when (1) the user bypasses a manual refresh in response to the post-deployment message and/or (2) the shift measure is between a refresh adjustment threshold and a notice threshold,
wherein the operation count is configured to trigger a refresh operation, and
wherein increasing the initial value corresponds to scheduling the refresh operation to occur earlier than without the increase.

### Claim 18

A method of operating a memory device that includes rewritable memory cells having initial levels of stored charges representative of preloaded data prior to an environmental stimulus, the method comprising:
dynamically generating a shift measure based on scanning the rewritable memory cells using a scan-read position,
wherein the shift measure represents one or more changes in the initial levels of the stored charges caused by the increased temperatures,
wherein the scan-read position is a threshold voltage different from an initial read position predetermined for reading the preloaded data; and
implementing a response action based on the shift measure to address the one or more changes in the initial levels and maintain accessibility for the preloaded data.

### Claim 19 (depends on 18)

The method of claim 18, wherein implementing the response action includes:
dynamically generating a post-deployment message for notifying a user that the preloaded data has been corrupted by the environmental stimulus; and
providing a manual refresh trigger that allows the user to selectively initiate a refresh operation for recovering the preloaded data.

### Claim 20 (depends on 18)

The method of claim 18, wherein implementing the response action includes:
based on the shift measure, increasing an initial value of an operation count representative of a number of performed memory access and/or activation operations,
wherein the operation count is configured to trigger a refresh operation, and
wherein increasing the initial value corresponds to scheduling the refresh operation to occur earlier than without the increase.