Memory Programming ISSP Pre-Charge for Disturbance Control

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Solution Overview

Problem

Existing memory programming methods face issues with hot carrier disturbance and read disturbance due to excessive common source line voltage, which can lead to programming disturbances in unselected memory cells.

Innovation Solution

Implement incremental-step-pulse programming (ISSP) for both common source line voltage and bit line voltage during pre-charge stages to manage electric fields and prevent hot carrier disturbance, ensuring adequate channel potential in unselected cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a large common source line voltage is applied to increase channel potential in unselected memory cells, then programming disturbance prevention is improved, but hot carrier disturbance increases causing read disturbance

Engineering Contradiction:

Improveprogramming disturbance preventionVSAvoidhot carrier disturbance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The common source line voltage is dynamically adjusted through incremental-step-pulse programming (ISSP) across multiple programming shots. The voltage starts at a lower level and gradually increases in steps, allowing the system to adaptively find the optimal voltage level that prevents programming disturbance while avoiding excessive voltage that would cause hot carrier disturbance. This dynamic adjustment resolves the contradiction by making the voltage level flexible rather than fixed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the voltage parameter through incremental steps in the ISSP method. By modifying the common source line voltage in controlled increments during pre-charge stages, the system achieves sufficient channel potential to prevent programming disturbance while limiting the maximum voltage to avoid hot carrier disturbance. This parameter change approach allows precise control over the voltage level to balance both requirements.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If the common source line voltage is reduced to prevent hot carrier disturbance, then read disturbance is reduced, but programming disturbance prevention capability decreases

Engineering Contradiction:

Improveread disturbanceVSAvoidprogramming disturbance prevention

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent employs periodic incremental-step-pulse programming actions across multiple programming shots. Instead of applying a single fixed voltage level, the system performs repeated voltage adjustment cycles where the common source line voltage is incrementally increased in each shot. This periodic action allows the system to build up sufficient voltage over time to prevent programming disturbance while keeping individual voltage steps low enough to avoid hot carrier disturbance.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The common source line voltage is preliminarily adjusted in pre-charge stages before the actual programming operation. By performing incremental voltage adjustments in advance through multiple pre-charge stages, the system prepares the unselected memory cells with adequate channel potential to prevent programming disturbance. This preliminary action ensures that when programming occurs, the voltage is already optimized to prevent both programming and read disturbance.

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Prevents hot carrier disturbance and reduces programming disturbances by controlling electric fields, maintaining optimal conditions for memory cell programming.

Implementation Method 1

preventing generation of the Fowler-Nordheim (FN) tunneling effect in the unselected memory cell

Methodology Applied

Scientific EffectFowler-Nordheim tunneling:

Implementation Method 2

induce hot carrier disturbance, increasing the threshold voltage of the unselected memory cell

Methodology Applied

Scientific EffectHot carrier disturbance:

Data Source

PatentUS12362018B2Method of programming memory

Publication Date: 2025.07.15 MACRONIX INTERNATIONAL CO LTD

AI summary

A method of programming a memory includes performing a plurality of programming shots is provided. Each programming shot includes a pre-charge stage and a programming stage and includes the following steps. Applying a common source line voltage to a common source line or applying a bit line voltage to a bit line in the pre-charge stage, wherein the common source line voltage or the bit line voltage is applied by using incremental-step-pulse programming (ISSP) in the plurality of pre-charge stages. Applying a programming voltage to a selected word line in the programming stage, wherein the programming voltage is applied by using ISSP in the plurality of programming stages.