Bi-directional sensing for 3D memory word-line interference
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Solution Overview
Problem
Semiconductor memory devices face challenges with neighboring word-line interference, which leads to high bit error rates during read operations in three-dimensional memory structures, as the shrinking memory structure increases interference effects.
Innovation Solution
Implementing bi-directional sensing methods, where memory cells are programmed using normal and reverse programming orders, and read using normal and reverse sensing operations based on the location of the word-line, to mitigate the impact of neighboring word-line interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory structures are shrunk to increase storage density, then storage capacity is improved, but neighboring word-line interference increases leading to higher bit error rates
Solution Approach 1:
The patent applies inversion by reversing the sensing direction for word-lines located at different positions. Specifically, even-numbered word-lines use a first sensing direction while odd-numbered word-lines use a second sensing direction opposite to the first. This inversion strategy compensates for the asymmetric interference patterns caused by neighboring word-lines in shrunk memory structures, thereby reducing bit error rates while maintaining high storage density
2Quantity of substance
If memory structures are shrunk to increase storage density, then storage capacity is improved, but neighboring word-line interference increases
Solution Approach 1:
The patent applies inversion by reversing the sensing direction for word-lines located at different positions. Specifically, even-numbered word-lines use a first sensing direction while odd-numbered word-lines use a second sensing direction opposite to the first. This inversion strategy compensates for the asymmetric interference patterns caused by neighboring word-lines in shrunk memory structures, thereby reducing bit error rates while maintaining high storage density
3Ease of operation
If normal sensing operation is applied to all word-lines, then operation simplicity is maintained, but bit error rates increase due to neighboring word-line interference
Solution Approach 1:
The patent applies local quality by differentiating the sensing operation based on the specific position of each word-line. Even-numbered word-lines undergo sensing operations in a first direction, while odd-numbered word-lines undergo sensing operations in an opposite second direction. This localized differentiation targets the interference problem specifically at affected word-line positions without complicating the overall operation framework, thereby reducing bit error rates while maintaining operational simplicity
Data Source
AI summary
A method reading memory using bi-directional sensing, including programming first memory cells coupled to a first word-line using a normal programming order; programming second memory cells coupled to a second word-line using a normal programming order; reading data from the first memory cells by applying a normal sensing operation to the first word-line; and reading data from the second memory cells by applying a reverse sensing operation to the second word-line. Methods also include receiving an error associated with reading data from the first memory cells; and then reading the data from the first memory cells by applying a reverse sensing operation to the first word-line. Method also include receiving an error associated with reading the data from the second memory cells; and then reading the data from the second memory cells by applying a normal sensing operation to the second word-line.