Vertical Channel Structure Void Prevention via Dielectric Segmentation
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Solution Overview
Problem
In 3D memory devices with vertical channel structures, voids in dielectric material can form during manufacturing, allowing conductive materials to enter and reduce device performance due to high aspect ratios, leading to potential performance issues.
Innovation Solution
A vertical channel structure is designed with a dielectric structure comprising a first low-temperature oxide layer and a second high-density plasma oxide layer, where the second layer seals the opening and forms a convex shape, preventing conductive materials from entering voids and enhancing plug contact area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a high aspect ratio VC hole structure is used to achieve higher storage density, then storage capability is improved, but void formation in dielectric material increases
Solution Approach 1:
The dielectric structure is segmented into two distinct layers: a first dielectric layer filling the VC hole and a second dielectric layer sealing the opening. This segmentation allows each layer to perform its specific function - the first layer provides filling while the second layer prevents void formation and conductive material intrusion.
Solution Approach 2:
The second dielectric layer is formed in advance to seal the opening before the conductive material formation process. This preliminary sealing action prevents conductive material from entering the VC hole, eliminating the need for subsequent repair or modification steps.
2Strength
If dielectric material is filled in the VC hole to support the structure, then structural integrity is improved, but voids are easily formed reducing reliability
Solution Approach 1:
The dielectric structure is divided into two functional layers: the first dielectric layer provides structural support by filling the VC hole, while the second dielectric layer ensures reliability by sealing the opening and preventing void formation and conductive material intrusion.
Solution Approach 2:
The second dielectric layer is formed in advance to seal the opening before any conductive material formation processes. This preliminary sealing action prevents potential reliability issues by blocking the path for conductive material to enter the VC hole.
3Quantity of substance
If the opening is enlarged to improve plug contact area, then device performance is improved, but conductive material may more easily enter voids
Solution Approach 1:
The dielectric structure is segmented into two layers where the second dielectric layer forms a seal around the opening. This segmentation allows the opening to be enlarged for better plug contact while the second layer maintains reliability by preventing conductive material from entering the VC hole.
Data Source
AI summary
A vertical channel structure including a substrate, a plurality of stacked structures, a charge storage structure, a channel structure and a dielectric structure is provided. The stacked structures are disposed on the substrate. An opening is located between the stacked structures. The charge storage structure is disposed on a sidewall of the opening. The channel structure is disposed on the charge storage structure and on the substrate at a bottom portion of the opening. The dielectric structure includes first and second dielectric layers. The first dielectric layer is disposed on the channel structure. The second dielectric layer is disposed on the first dielectric layer and seals the opening to form a void in the dielectric structure. A top portion of the second dielectric layer is higher than a top portion of the first dielectric layer. The dielectric structure exposes an upper portion of the channel structure.