Flash Memory Programming Method for False Cell Detection

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Solution Overview

Problem

Flash memory devices face reliability issues due to false programming of memory cells, where program-inhibited cells are mistakenly programmed, leading to read errors and inefficient operation.

Innovation Solution

A flash memory device with a programming method that involves sensing the states of programmed memory cells, latching these states, and determining whether program-inhibited cells have been correctly programmed before confirming the programming status, using a reading/writing circuit and control logic circuit to reserve data and control the programming process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the programming operation is terminated based on traditional verification method, then the programming speed is improved, but the reliability deteriorates due to false programming of program-inhibited cells

Engineering Contradiction:

Improveprogramming speedVSAvoidprogramming accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent segments the verification process into two distinct stages: first verifying program-inhibited cells to detect false programming, and then verifying program cells. This segmentation allows the system to terminate early when false programming is detected, improving reliability while maintaining efficient programming speed through selective verification.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary verification of program-inhibited cells before completing the full programming operation. By checking program-inhibited cells first and detecting false programming early, the system prevents unnecessary continued programming and avoids read errors, thereby improving reliability without significantly impacting overall programming speed.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If all selected memory cells are verified to determine proper programming, then the reliability is improved, but the programming time increases due to unnecessary verification of program-inhibited cells

Engineering Contradiction:

Improveprogramming accuracyVSAvoidprogramming time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The verification process is divided into two separate verification operations: first verifying program-inhibited cells, then verifying program cells. This segmentation allows the system to terminate the entire verification process early if false programming is detected in program-inhibited cells, avoiding unnecessary verification time while maintaining reliability through selective verification.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs only the necessary partial verification of program-inhibited cells first, and conditionally proceeds to verify program cells only if needed. This partial action approach ensures reliability by verifying critical cells while minimizing total verification time by avoiding unnecessary verification when false programming is detected early.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS8194463B2Flash memory device and programming method thereof

Publication Date: 2012.06.05 SAMSUNG ELECTRONICS CO LTD

AI summary

A programming method of a flash memory device having memory cells, and a flash memory device to perform the method, including programming selected memory cells according to loaded data, sensing states of the programmed memory cells and firstly latching the sensed states, and determining whether a program-inhibited memory cell among the selected memory cells has been programmed, with reference to the loaded data and the latched states, before determining whether the selected memory cells have been properly programmed.