Conductive Structure Thickness Layout to Prevent 3D NAND Collapse
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Solution Overview
Problem
During the fabrication of vertically-stacked memory, such as three-dimensional NAND, unintended etching of supporting semiconductor material can lead to the collapse of structures due to exposure of metal-containing conductive material, resulting in device failure.
Innovation Solution
Providing thickened regions of semiconductor material at locations where etching would otherwise expose the underlying metal-containing conductive material, preventing galvanic corrosion and subsequent material removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard thickness semiconductor material is used throughout the conductive structure, then manufacturing simplicity is maintained, but galvanic corrosion occurs during etching when metal-containing conductive material is exposed
Solution Approach 1:
The patent applies local quality by varying the thickness of semiconductor material in different regions of the conductive structure. Specifically, a first region has a first thickness and a second region has a second thickness that is less than the first thickness. This localized thickness variation prevents galvanic corrosion in the first region while maintaining structural integrity, rather than uniformly increasing thickness throughout the entire structure.
Solution Approach 2:
The patent implements preliminary action by pre-forming the conductive structure with non-uniform semiconductor material thickness before the etching process. The thicker first region is intentionally created in advance to prevent galvanic corrosion during subsequent etching operations, proactively addressing the corrosion issue before it can occur rather than attempting to fix it after exposure.
2Reliability
If thicker semiconductor material is provided in regions prone to etching exposure, then galvanic corrosion is prevented, but manufacturing complexity increases
Solution Approach 1:
The patent makes different parts of the conductive structure have different semiconductor material thicknesses to provide corrosion resistance only where needed. The first region has greater thickness for corrosion protection, while the second region maintains standard thickness, avoiding unnecessary material addition and simplifying manufacturing compared to uniformly thickening the entire structure.
Solution Approach 2:
The patent changes the thickness parameter of semiconductor material in specific regions of the conductive structure. By adjusting the thickness parameter locally rather than globally, the invention achieves corrosion protection while minimizing the impact on manufacturing processes and overall device complexity.
3Productivity
If uniform etching is applied across the conductive structure, then manufacturing simplicity is maintained, but unintended material removal occurs exposing metal-containing conductive material
Solution Approach 1:
The patent performs preliminary action by pre-configuring the conductive structure with varied semiconductor material thicknesses before etching. This preliminary thickness variation ensures that during uniform etching operations, the thicker first region protects underlying metal-containing conductive material from exposure, while allowing controlled material removal in thinner regions without compromising structural integrity.
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 approach prevents the collapse of vertically-stacked structures and enhances the reliability of the memory array by maintaining the integrity of the semiconductor material during processing.
Implementation Method 1
unintended etching of supporting semiconductor material can lead to the collapse of structures due to exposure of metal-containing conductive material, resulting in device failure
Data Source
AI summary
Some embodiments include an integrated assembly having a conductive structure which includes a semiconductor material over a metal-containing material. A stack of alternating conductive levels and insulative levels is over the conductive structure. A partition extends through the stack. The partition has wall regions, and has corner regions where two or more wall regions meet. The conductive structure includes a first portion which extends directly under the corner regions, and includes a second portion which is directly under the wall regions and is not directly under the corner regions. The first portion has a first thickness of the semiconductor material and the second portion has a second thickness of the semiconductor material. The first thickness is greater than the second thickness. Some embodiments include methods of forming integrated assemblies.