3D Memory Source Contact Structure for Slit Deformation Control

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Solution Overview

Problem

Existing 3D NAND memory devices face challenges in storage capacity 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 interleaved conductor and insulating layers, featuring source contacts separated by support structures connected through an adhesion layer, which reduces resistance and mitigates deformation during fabrication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gate line slits are formed during fabrication, then memory cells can be constructed, but deformation occurs leading to electrical leakage and misalignment

Engineering Contradiction:

Improveelectrical leakage preventionVSAvoidgate line slit alignment

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The gate line structure is divided into multiple segments separated by support structures. This segmentation prevents continuous deformation across the entire gate line, isolating potential misalignment issues to individual segments while maintaining overall functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Support structures are introduced as intermediary elements between adjacent gate line slits. These support structures provide mechanical stabilization and prevent deformation, acting as mediators that maintain the structural integrity and alignment of the gate line slits during fabrication and operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If source contacts are separated by support structures, then structural stability is improved, but resistance increases due to separation

Engineering Contradiction:

Improvesource contact structure stabilityVSAvoidelectrical resistance

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

An adhesion layer is introduced as an intermediary conductive element between the separated source contacts. This adhesion layer serves dual purposes: it provides mechanical connection and electrical conductivity, bridging the gap created by support structures while maintaining low resistance pathways for current flow.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The source contact structure is formed as a composite of multiple materials including the adhesion layer and conductive material. This composite structure combines the mechanical stability provided by support structures with the electrical conductivity of the adhesion layer and conductive material, achieving both structural integrity and low resistance.

Inventive Principle:

Principle #40Composite materials

3Reliability

If adhesion layer is added to connect source contacts, then resistance is reduced, but fabrication complexity increases

Engineering Contradiction:

Improvesource contact conductivityVSAvoidfabrication process steps

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The adhesion layer performs multiple functions simultaneously: it provides mechanical adhesion between source contacts and support structures, establishes electrical conductivity pathways, and serves as part of the overall structural framework. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in fabrication complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 configuration enhances the stability and performance of 3D memory devices by reducing resistance and preventing deformation, thereby improving storage capacity and reducing fabrication costs.

Implementation Method 1

At least a portion of the adhesion layer is between the first and second source contacts and conductively connects the first and second source contacts

Methodology Applied

Scientific EffectElectrical Conduction: Conduction (electrical)

Data Source

PatentUS11758723B2Three-dimensional memory device with source contacts connected by an adhesion layer and methods for forming the same

Publication Date: 2023.09.12 YANGTZE MEMORY TECH CO LTD

AI summary

A method for forming a three-dimensional (3D) memory device includes forming a cut structure in a stack structure. The stack structure includes interleaved a plurality of initial sacrificial layers and a plurality of initial insulating layers. The method also includes removing portions of the stack structure adjacent to the cut structure to form a slit structure and an initial support structure. The initial support structure divides the slit structure into a plurality of slit openings. The method further includes forming a plurality of conductor portions in the initial support structure through the plurality of slit openings. The method also includes forming a source contact in each of the plurality of slit openings. The method also includes removing portions of the initial support structure to form a support structure. The support structure includes an adhesion portion extending through the support structure. In addition, the method includes forming an adhesion layer over the source contact in each of the plurality of slit openings. At least two adhesion layers are conductively connected to the adhesion portion extending through the support structure.