3D Memory Source Structure Adhesion Layer Deformation

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Solution Overview

Problem

Existing 3D NAND memory devices face challenges in storage density and cost due to deformation of gate line slits during fabrication, leading to electrical leakage and misalignment, which affects the performance and reliability of the memory cells.

Innovation Solution

The implementation of a 3D memory device with source structures that include support structures dividing the source into sections, where an adhesion layer conductsively connects these sections, reducing resistance and mitigating deformation during fabrication by providing electrical connectivity through a single contact plug.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gate line slits are used in 3D NAND memory devices, then electrical connectivity is achieved, but deformation occurs during fabrication leading to electrical leakage and misalignment

Engineering Contradiction:

Improveelectrical connectivityVSAvoidalignment precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The source structure is divided into multiple sections by support structures, with each section containing source contacts. The adhesion layer segments the electrical connection path through these sections, allowing independent formation and reducing mutual interference during fabrication, thereby improving alignment precision while maintaining electrical connectivity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An adhesion layer is introduced as an intermediary component between source contacts and support structures. This adhesion layer not only provides mechanical bonding but also serves as a conductive pathway, mediating the electrical connection between divided source sections while reducing susceptibility to deformation

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If source structures are divided into sections by support structures, then deformation susceptibility is reduced, but resistance increases due to multiple connection points

Engineering Contradiction:

Improvestructural stabilityVSAvoidelectrical resistance

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The source structure employs a composite design combining conductive materials (source contacts) with adhesive materials (adhesion layer). The adhesion layer material is specifically selected to provide both mechanical bonding strength and electrical conductivity, creating a composite structure that simultaneously reduces deformation susceptibility and maintains low resistance

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The adhesion layer acts as a dual-function intermediary that provides both mechanical support (reducing deformation) and electrical conduction (maintaining connectivity). By choosing materials with appropriate properties for the adhesion layer, both structural stability and electrical performance are optimized

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If adhesion layer is deposited to connect source sections, then electrical connectivity is improved, but fabrication complexity increases

Engineering Contradiction:

Improveelectrical connectivityVSAvoidfabrication process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The adhesion layer deposition is merged with existing fabrication processes such as atomic layer deposition (ALD) or chemical vapor deposition (CVD) steps already used for forming other device components. This integration allows the adhesion layer to be formed without adding significant process complexity, while still providing the necessary electrical connectivity between source sections

Inventive Principle:

Principle #5Merging (Combining)

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

This solution enhances the reliability and performance of 3D NAND memory devices by reducing resistance and susceptibility to deformation, thereby improving storage density and reducing fabrication costs.

Implementation Method 1

At least a portion of the adhesion layer extends through the support structure and conductively connects the first and second sections

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS11043565B2Three-dimensional memory device with source contacts connected by an adhesion layer and methods for forming the same

Publication Date: 2021.06.22 YANGTZE MEMORY TECH CO LTD

AI summary

A three-dimensional (3D) memory device includes a memory stack over a substrate. The memory stack includes interleaved a plurality of conductor layers and a plurality of insulating layers. The 3D memory device also includes a plurality of channel structures extending vertically in the memory stack. The 3D memory device further includes a source structure extending in the memory stack. The source structure includes a support structure dividing the source structure into first and second sections. The source structure also includes an adhesion layer. At least a portion of the adhesion layer extends through the support structure and conductively connects the first and second sections.