Memory Access Line Contacts for Defect-Tolerant Data Integrity

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Solution Overview

Problem

Defective access line contacts in memory devices lead to data errors and SAD failures, which can result in uncorrectable errors and improper device functioning, despite the presence of error correction code (ECC) circuitry.

Innovation Solution

Coupling a single memory cell access line to a local access line via multiple access line contacts to compensate for defective contacts, ensuring data integrity by allowing an additional contact to be used if the first is defective.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single access line contact is used to couple the memory cell access line to the local access line, then the device complexity is reduced, but the reliability deteriorates due to potential contact defects causing data errors and SAD failures

Engineering Contradiction:

Improveaccess line contact reliabilityVSAvoidaccess line contact structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the access line contact function into multiple separate contacts instead of using a single contact. Each contact is independently formed to couple the memory cell access line to the local access line, so that a defect in one contact does not necessarily cause failure of the entire access line. This segmentation of the contact function improves reliability while maintaining reasonable structural complexity.

Inventive Principle:

Principle #1Segmentation

2Reliability

If multiple access line contacts are formed to compensate for defective contacts, then the reliability is improved, but the manufacturing precision requirements increase

Engineering Contradiction:

Improveaccess line contact reliabilityVSAvoidaccess line contact formation precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent forms multiple access line contacts (excessive action) to ensure that even if one or more contacts are defective, the access line functionality is maintained. By forming more contacts than the minimum single contact requirement, the system tolerates manufacturing variations and defects while still achieving reliable operation.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If multiple access line contacts are used, then the likelihood of errors is reduced, but the device complexity increases due to additional contacts and coupling structures

Engineering Contradiction:

Improvedata integrityVSAvoidaccess line contact structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple access line contacts into a unified coupling structure that connects the memory cell access line to the local access line. By merging the multiple contacts into an integrated structure rather than treating them as separate independent components, the design achieves improved reliability while controlling the increase in device complexity through structural consolidation.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS12451211B2Access line contacts for an access line in a memory device

Publication Date: 2025.10.21 MICRON TECHNOLOGY INC

AI summary

Systems, methods, and apparatuses related to determining a number of access line contacts for an access line in a memory device are described. An apparatus includes a first data plane, a second data plane, and a sub-access line driver (SAD), all coupled to a local access line. A first portion of the local access line between the SAD and the first data plane includes a first number of access line contacts, a second portion of the local access line between the SAD and the second data plane includes a second number of access line contacts, and the first number of access line contacts are determined by data corresponding to a first function of the first data plane and the second number of access line contacts are determined by data corresponding to a second function of the data plane.