Non-Volatile Memory Verify Control for Suspend-Resume Programming
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Solution Overview
Problem
Non-volatile memory devices experience degradation of program threshold voltage distribution and reliability due to suspend-resume operations during program operations, leading to potential read failures.
Innovation Solution
A non-volatile memory device and method that perform an initial program verify operation using a different verify condition during suspend and resume commands, followed by a normal program verify operation with distinct voltage levels and times, to maintain program threshold voltage distribution integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a suspend-resume operation is performed during a program operation of non-volatile memory devices, then read operations can be executed during programming, but the program threshold voltage distribution degrades and reliability decreases
Solution Approach 1:
The patent applies preliminary action by performing an initial program verify operation at the moment of suspend command reception, before the actual suspend-resume interval occurs. This initial verification captures the threshold voltage state at a known good point in time, establishing a reference that compensates for subsequent drift during the suspend period. The initial verify condition is specifically designed to be more stringent than normal verify conditions to account for expected threshold voltage shifts during suspension.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting verify conditions based on operation type. Two distinct verify condition sets are used: initial program verify conditions applied during suspend-resume operations, and normal program verify conditions applied during continuous programming. The initial verify conditions include different voltage thresholds and timing parameters specifically calibrated to compensate for the suspend-resume interval effects on threshold voltage distribution.
2Productivity
If a suspend-resume operation is performed during a program operation of non-volatile memory devices, then read operations can be executed during programming, but the time interval causes degradation of program threshold voltage distribution
Solution Approach 1:
The patent applies preliminary action by performing an initial program verify operation at the moment of suspend command reception, before the actual suspend-resume interval occurs. This initial verification captures the threshold voltage state at a known good point in time, establishing a reference that compensates for subsequent drift during the suspend period. The initial verify condition is specifically designed to be more stringent than normal verify conditions to account for expected threshold voltage shifts during suspension.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting verify conditions based on operation type. Two distinct verify condition sets are used: initial program verify conditions applied during suspend-resume operations, and normal program verify conditions applied during continuous programming. The initial verify conditions include different voltage thresholds and timing parameters specifically calibrated to compensate for the suspend-resume interval effects on threshold voltage distribution.
3Productivity
If a suspend-resume operation is performed during a program operation of non-volatile memory devices, then read operations can be executed during programming, but reliability of the memory device decreases
Solution Approach 1:
The patent applies preliminary action by performing an initial program verify operation at the moment of suspend command reception, before the actual suspend-resume interval occurs. This initial verification captures the threshold voltage state at a known good point in time, establishing a reference that compensates for subsequent drift during the suspend period. The initial verify condition is specifically designed to be more stringent than normal verify conditions to account for expected threshold voltage shifts during suspension.
Solution Approach 2:
The patent implements feedback by using the initial program verify results to adjust and compensate for threshold voltage shifts that occur during the suspend-resume interval. The system continuously monitors threshold voltage distribution through the initial verify operation and uses this information to correct programming parameters, ensuring that final threshold voltage targets are met despite the suspend-resume disruption. This closed-loop feedback mechanism maintains reliability even when read operations interrupt programming.
Data Source
AI summary
A non-volatile memory device includes a memory cell array including memory cells respectively connected to bit lines; and a control logic unit configured to control a program operation with respect to the memory cells. The control logic unit is configured to perform a normal program verify operation with respect to the memory cells by using a normal program verify condition, during the program operation, and, based on a suspend command that is received during the program operation, perform an initial program verify operation with respect to the memory cells by using an initial program verify condition that is different from the normal program verify condition.