Nonvolatile Memory Device Process Capability Index Adjustment
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Solution Overview
Problem
Nonvolatile memory devices face challenges in maintaining optimal operation conditions due to deviations from target shapes in memory cell structures, leading to inefficiencies in program, read, and erase operations.
Innovation Solution
A method and system that utilize a process capability index to adjust operation conditions such as voltage and time for program, read, and erase operations based on the deviation of memory cell structures from target shapes, using a memory controller to read and manage the process capability index stored in a table format, and applying these adjustments to ensure optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If memory cell structures are manufactured with standard fabrication processes, then manufacturing cost and complexity are kept low, but structural deviations from target shapes occur leading to suboptimal operation conditions
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing process capability indices for different memory block locations before actual operation. The memory controller reads these pre-stored PCI values and uses them to determine appropriate operation conditions, eliminating the need for real-time complex calculations and reducing operational complexity while maintaining high manufacturing precision requirements
Solution Approach 2:
The patent changes operational parameters (voltage levels, pulse widths, current values) based on the process capability index that reflects structural deviations. By dynamically adjusting these parameters according to the PCI, the system compensates for manufacturing variations without requiring perfect manufacturing precision, thus resolving the contradiction between maintaining high precision and managing complexity
2Reliability
If operation conditions are optimized for each memory block based on structural deviations, then operation reliability is improved, but control complexity and measurement requirements increase
Solution Approach 1:
The patent uses copying by storing process capability index values in a lookup table or memory structure that can be quickly referenced. Instead of performing complex real-time measurements and calculations, the system copies pre-determined PCI values from storage based on memory block location, significantly reducing measurement and control complexity while maintaining reliable operation conditions
Solution Approach 2:
The process capability indices are determined and stored in advance for different memory block locations. This preliminary characterization allows the memory controller to quickly retrieve appropriate PCI values without performing complex measurements during operation, thereby improving reliability while minimizing the difficulty of detection and measurement
3Productivity
If uniform operation conditions are used across all memory blocks, then control simplicity is maintained, but operation efficiency decreases due to structural variations
Solution Approach 1:
The patent applies local quality by assigning different operation conditions to different memory block locations based on their specific process capability indices. Each memory block receives customized voltage, time, and current parameters tailored to its structural characteristics, maximizing operation efficiency for each local region while the overall system maintains manageable complexity through systematic organization
Solution Approach 2:
The patent segments the memory device into multiple blocks with distinct operation conditions based on their process capability indices. By dividing the memory space and assigning optimized parameters to each segment, the system achieves high overall productivity through localized optimization without creating unmanageable system complexity
Data Source
AI summary
According to example embodiments, a method of operating a storage device includes reading a process capability index using a memory controller, adjusting at least one operation condition based on the process capability index, and operating one of at least one nonvolatile memory device according to the at least one operation condition adjusted. The process capability index indicates how a structure associated with a memory cell to be operated deviates from a target shape.