Memory Deck Erase Policy Selection for Read Window Reliability

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Solution Overview

Problem

Existing erase policies for memory devices with multiple decks do not account for defective and functional decks, leading to increased error rates and reliability issues due to residual holes trapped in the semiconductor substrate, affecting threshold voltage distributions and read window budgets.

Innovation Solution

Adaptive selection of erase policies based on memory reliability metrics, such as read window budget (RWB), to apply different delay times for erasing memory cells in functional and defective decks, using zero-delay and non-zero-delay policies to minimize threshold voltage shifts and improve reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a uniform erase policy is applied to all decks in a memory device, then the implementation is simple and consistent, but defective decks experience increased error rates and reliability issues due to residual holes trapped in the semiconductor substrate

Engineering Contradiction:

Improveerase policy implementation simplicityVSAvoidmemory device reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent applies different erase policies to different decks based on their functional status. Functional decks use one erase policy while defective decks use a different erase policy, allowing each deck to be treated according to its specific quality characteristics rather than applying a uniform policy to all decks

Inventive Principle:

Principle #3Local quality

2Productivity

If zero-delay erase policy is used for fast memory operations, then productivity is improved, but threshold voltage shifts and read window budget depletion occur affecting measurement precision

Engineering Contradiction:

Improvememory operation speedVSAvoidread window budget

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent dynamically selects between zero-delay and non-zero-delay erase policies based on the deck's functional status and operational requirements. The erase policy is not fixed but adapts to the specific conditions of each deck, allowing the system to optimize between speed and precision depending on the deck's characteristics

Inventive Principle:

Principle #15Dynamics

3Measurement precision

If non-zero-delay erase policy is applied to maintain read window budget, then measurement precision is preserved, but productivity decreases due to increased delay time

Engineering Contradiction:

Improveread window budget maintenanceVSAvoidmemory operation throughput

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20260017189A1Selection of erase policy in a memory device

Publication Date: 2026.01.15 MICRON TECHNOLOGY INC

AI summary

A system includes a memory device and a processing device, operatively coupled with the memory device, to perform operations including: identifying, among a first deck having a first memory reliability metric and a second deck having a second memory reliability metric, a deck comprising a set of memory cells; and causing an erase operation to be performed with respect to the set of memory cells in accordance with the erase policy associated with the identified deck.