Smart Verify Voltage Acquisition for Memory Programming
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Solution Overview
Problem
Existing non-volatile memory apparatuses face issues with smart verify programming voltage inconsistencies, leading to over-programming or decreased performance due to defects in memory devices, which affect programming time and data integrity.
Innovation Solution
A memory apparatus and method that includes memory cells connected to word lines and organized in strings, with a control means to program and acquire a smart verify programming voltage, and discard it if the number of smart verify loops exceeds predetermined criteria, determining another voltage for subsequent strings to ensure reliable programming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If smart verify programming voltage is acquired from sampling string to improve program speed, then programming time is reduced, but defects can cause the voltage to be too high or too low leading to over programming or decreased apparatus performance
Solution Approach 1:
The patent implements a feedback mechanism where the smart verify programming voltage acquired from a sampling string is evaluated against pass/fail criteria before being applied to subsequent strings. If the acquired voltage fails the criteria (indicating potential defects), the system detects this and prevents using the unreliable voltage, thereby maintaining programming reliability while still allowing speed improvements when conditions are good.
Solution Approach 2:
The patent performs preliminary evaluation of the smart verify programming voltage by conducting smart verify loops on a sampling string before applying the voltage to actual data strings. This preliminary action identifies potential defects early, allowing the system to discard unreliable voltages before they cause over-programming or performance degradation, thus ensuring reliability while maintaining the speed benefits of smart verify when applicable.
2Reliability
If smart verify operation is performed on all strings to ensure reliable voltage acquisition, then programming voltage reliability is improved, but programming time increases
Solution Approach 1:
The patent segments the smart verify process into two distinct parts: (1) a sampling string operation where smart verify loops are performed to acquire and evaluate the programming voltage, and (2) subsequent data string operations where the evaluated voltage is applied. This segmentation allows reliable voltage acquisition through sampling while avoiding redundant smart verify operations on all strings, thus maintaining reliability without excessive programming time penalty.
Solution Approach 2:
The patent uses a sampling string as a copy or representative sample to determine the appropriate smart verify programming voltage that will be applied to subsequent data strings. By performing the expensive smart verify loops on a single sampling string rather than all strings, the system obtains a reliable voltage value that can be copied and reused, significantly reducing total programming time while maintaining voltage reliability.
Data Source
AI summary
A memory apparatus and operating method are provided. The apparatus includes memory cells connected to word lines and disposed in memory holes and configured to retain a threshold voltage. The memory holes are organized in rows grouped in strings. A control means is coupled to the word lines and the memory holes and programs the memory cells associated with a first one of the strings in a program operation and acquire a smart verify programming voltage in a smart verify operation including smart verify loops. The control means discards the smart verify programming voltage and determines another smart verify programming voltage in another smart verify operation on the memory cells associated with a second one of the strings in response to a quantity of the smart verify loops needed to complete programming of the memory cells associated with the first one of the strings being outside a predetermined threshold criteria.