3D Memory Cell Programming with Alternating Program Loops
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Solution Overview
Problem
In nonvolatile memory devices with a 3D structure, the threshold voltages of memory cells in one physical page can inadvertently affect neighboring pages, leading to inconsistent and undesired changes in their threshold voltages during program operations.
Innovation Solution
A method is implemented where program loops are alternately performed on first and second memory pages coupled to a word line, involving program and verify operations to raise the threshold voltages of memory cells in each page to target levels, using a program operation controller to manage these loops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If program operation is sequentially performed on multiple physical pages coupled to one word line, then program operation can be completed on all pages, but threshold voltage changes in one page affect other pages causing inconsistent threshold voltage distributions
Solution Approach 1:
The patent divides the program operation into multiple alternating loops, where each loop targets a specific physical page (first page or second page) coupled to the same word line. By segmenting the program operation and alternating between pages, the patent prevents threshold voltage changes in one page from affecting other pages, thus maintaining consistent threshold voltage distributions while still completing program operations on all pages.
2Quantity of substance
If program operation is performed on all physical pages, then data storage capacity is utilized, but threshold voltages of memory cells in different pages become inconsistent
Solution Approach 1:
The patent implements periodic action by alternating between program operations on the first physical page and the second physical page in repeated loops. This periodic alternation ensures that each page receives focused program attention without interference from neighboring pages, maintaining precise threshold voltage control while utilizing full data storage capacity across all physical pages.
Data Source
AI summary
Provided herein may be a memory device for performing a program operation including program loops and a method of operating the same. The method of operating a memory device may include performing a first program loop of increasing threshold voltages of first memory cells selected by a first drain select line among a plurality of memory cells coupled to a word line, performing a second program loop of increasing threshold voltages of second memory cells selected by a second drain select line among the plurality of memory cells, and alternately repeating the first program loop and the second program loop such that respective threshold voltages of the first memory cells and the second memory cells are increased to respective threshold voltages corresponding to respective target program states.