Memory Controller Randomizer for 3D NAND Sub-Block Data Randomness

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Solution Overview

Problem

Existing semiconductor memory devices face challenges in maintaining data randomness, particularly in three-dimensional structures, where the integration of multiple sub-blocks can lead to reduced randomness and operational performance due to uneven threshold voltage distributions across memory cells.

Innovation Solution

A memory controller with a randomizer that generates randomized data by selecting a seed table based on sub-block information, ensuring each sub-block receives independently randomized data, thereby improving data randomness in the string direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If multiple sub-blocks are integrated in three-dimensional memory structures to increase storage capacity, then the storage density is improved, but the data randomness deteriorates due to uneven threshold voltage distributions across memory cells

Engineering Contradiction:

Improvestorage capacityVSAvoiddata randomness

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The memory block is divided into multiple sub-blocks, and separate randomizer circuits are assigned to each sub-block. This segmentation allows independent randomization operations on data stored in each sub-block, preventing the propagation of threshold voltage distribution issues across the entire memory block and maintaining data randomness despite the three-dimensional integrated structure

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different randomizer circuits are configured for different sub-blocks based on their specific threshold voltage characteristics. Each randomizer is locally optimized to compensate for the specific uneven threshold voltage distribution in its assigned sub-block, thereby maintaining data randomness at the local level across the entire three-dimensional memory structure

Inventive Principle:

Principle #3Local quality

2Reliability

If independent randomizer circuits are configured for each sub-block to maintain data randomness, then the data randomness is improved, but the device complexity increases

Engineering Contradiction:

Improvedata randomnessVSAvoidrandomizer circuit configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The randomizer circuits across different sub-blocks are designed with a universal architecture and operational protocol. Each randomizer performs the same fundamental randomization function using similar circuit topologies, allowing for standardized design, simplified manufacturing, and easier control despite being distributed across multiple sub-blocks

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11269556B2Semiconductor memory device and memory controller having randomizer

Publication Date: 2022.03.08 MIMIRIP LLC

AI summary

A memory controller for controlling an operation of a semiconductor memory device including a memory block including a plurality of sub-blocks. The memory controller includes a randomizer. The randomizer includes: seed table storage configured to store a plurality of seed tables respectively corresponding to the plurality of sub-blocks, and to generate a seed, based on sub-block information of received original data; a random sequence generator configured to generate a random sequence, based on the seed generated by the seed table storage; and an operating component configured to generate random data, based on the random sequence and the original data.