# US 2023/0056938 A1 · Defect detection in memory based on active monitoring of read operations > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0056938 A1 - Document ID: US20230056938A1 - Status: Published application - Kind: A1 - Application number: 17/972,230 - Filed: 2022-10-24 - Published: 2023-02-23 - Earliest claimed: 2021-08-18 - Assignees: Micron Technology, Inc. - Applicants: Micron Technology, Inc. - Inventors: Zhenlei Shen; Tingjun Xie; Frederick Adi; Zhenming Zhou - Web page: https://patentgrep.com/patent/US20230056938A1 ## CPC - G06F 11/073: {in a memory management context, e.g. virtual memory or cache management (memory management G06F12/00; testing of static memory units G11C29/00)} - G06F 11/1068: {in sector programmable memories, e.g. flash disk (G06F11/1072 takes precedence)} - G06F 11/0757: {by exceeding a time limit, i.e. time-out, e.g. watchdogs} - G06F 11/076: {by exceeding a count or rate limit, e.g. word- or bit count limit} - G06F 11/0772: {Means for error signaling, e.g. using interrupts, exception flags, dedicated error registers} - G06F 11/3037: {where the computing system component is a memory, e.g. virtual memory, cache (accessing, addressing or allocating within memory systems or architectures G06F12/00; checking stores for correct operation G11C29/00)} - G06F 11/0793: {Remedial or corrective actions (recovery from an exception in an instruction pipeline G06F9/3861; by retry G06F11/1402; for recovering from a failure of a protocol instance or entity H04L69/40)} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract A first error rate based on a first read operation performed on a memory device is obtained. An individual data unit of the memory device that satisfies a first threshold criterion associated with a defect candidate is determined. A defect verification operation on the individual data unit to obtain a second error rate is performed. The individual data unit that satisfies a second threshold criterion associated with a defect is determined. ## Claims ### Claim 1 A system comprising: a memory device; and a processing device, operatively coupled with the memory device, to perform operations comprising: determining whether a first error rate of an individual data unit of the memory device satisfies a first threshold criterion associated with identifying a defect candidate; responsive to determining that the first error rate satisfies the first threshold criterion, obtaining a second error rate of the individual data unit; determining whether the second error rate satisfies a second threshold criterion associated with identifying a defect; and responsive to determining that the second error rate satisfies the second threshold criterion, marking the individual data unit as defective. ### Claim 2 (depends on 1) The system of claim 1, wherein obtaining a second error rate of the individual data unit comprises: re-writing data to the individual data unit; performing a second read operation on the individual data unit after a predetermined period of time; and returning the second error rate. ### Claim 3 (depends on 1) The system of claim 1, wherein the first threshold criterion is satisfied if the first error rate is greater than or equal to a first threshold. ### Claim 4 (depends on 3) The system of claim 3, wherein the second threshold criterion is satisfied if the second error rate is greater than or equal to a second threshold. ### Claim 5 (depends on 4) The system of claim 4, wherein the first threshold is configured to be greater than the second threshold based on a predetermined period of time. ### Claim 6 (depends on 5) The system of claim 5, wherein the predetermined period of time is configured to eliminate extrinsic factors acting on the memory device. ### Claim 7 (depends on 1) The system of claim 1, wherein the first error rate and the second error rate correspond to a number of directional bit errors. ### Claim 8 (depends on 1) The system of claim 1, wherein marking the individual data unit as defective comprises removing the individual data unit from further use. ### Claim 9 A method comprising: determining whether a first error rate of an individual data unit of a memory device satisfies a first threshold criterion associated with identifying a defect candidate; responsive to determining that the first error rate satisfies the first threshold criterion, obtaining a second error rate of the individual data unit; determining whether the second error rate satisfies a second threshold criterion associated with identifying a defect; and responsive to determining that the second error rate satisfies the second threshold criterion, marking the individual data unit as defective. ### Claim 10 (depends on 9) The method of claim 9, wherein obtaining a second error rate of the individual data unit comprises: re-writing data to the individual data unit; performing a second read operation on the individual data unit after a predetermined period of time; and returning the second error rate. ### Claim 11 (depends on 9) The method of claim 9, wherein the first threshold criterion is satisfied if the first error rate is greater than or equal to a first threshold. ### Claim 12 (depends on 11) The method of claim 11, wherein the second threshold criterion is satisfied if the second error rate is greater than or equal to a second threshold. ### Claim 13 (depends on 12) The method of claim 12, wherein the first threshold is configured to be greater than the second threshold based on a predetermined period of time. ### Claim 14 (depends on 13) The method of claim 13, wherein the predetermined period of time is configured to eliminate extrinsic factors acting on the memory device. ### Claim 15 (depends on 9) The method of claim 9, wherein the first error rate and the second error rate is a number of directional bit errors. ### Claim 16 (depends on 9) The method of claim 9, wherein marking the individual data unit as defective comprises removing the individual data unit from further use. ### Claim 17 A non-transitory computer-readable storage medium comprising instructions that, when executed by a processing device, cause the processing device to perform operations comprising: determining whether a first error rate of an individual data unit of a memory device satisfies a first threshold criterion associated with identifying a defect candidate; responsive to determining that the first error rate satisfies the first threshold criterion, obtaining a second error rate of the individual data unit; determining whether the second error rate satisfies a second threshold criterion associated with identifying a defect; and responsive to determining that the second error rate satisfies the second threshold criterion, marking the individual data unit as defective. ### Claim 18 (depends on 17) The non-transitory computer-readable storage medium of claim 17, wherein obtaining a second error rate of the individual data unit comprises: re-writing the data of the individual data unit; performing a second read operation on the individual data unit after a predetermined period of time; and returning the second error rate. ### Claim 19 (depends on 17) The non-transitory computer-readable storage medium of claim 17, wherein the first threshold criterion is satisfied if the first error rate is greater than or equal to a first threshold. ### Claim 20 (depends on 19) The non-transitory computer-readable storage medium of claim 19, wherein the second threshold criterion is satisfied if the second error rate is greater than or equal to a second threshold.