H-Shaped Block Nonvolatile Memory Device for Etching Uniformity
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Solution Overview
Problem
The integration density of nonvolatile memory devices is limited by the complexity of the three-dimensional structure, which can lead to reliability issues due to the leaning phenomenon of blocks cut by word line trenches, affecting the dispersion and etching uniformity in the mold structures.
Innovation Solution
A nonvolatile memory device with a substrate and mold structures featuring interconnected stacks and trenches, where the second mold structure includes connecting parts to support and connect blocks, reducing the leaning of blocks and improving product reliability by enhancing the dispersion at the lower parts of the mold structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the integration density of nonvolatile memory devices is increased by developing three-dimensional structures, then the storage capacity is improved, but the reliability deteriorates due to the leaning phenomenon of blocks cut by word line trenches
Solution Approach 1:
The memory device is divided into multiple blocks separated by block trenches. The first mold structure is completely cut by block trenches to form separate blocks, while the second mold structure is partially cut to expose portions of the first mold structure's block trenches. This segmentation prevents the leaning phenomenon from affecting the entire structure uniformly and isolates potential failure points.
Solution Approach 2:
Different regions of the mold structures have different trench configurations. The first mold structure has complete block trenches providing full separation, while the second mold structure has partial block trenches that expose portions of the first mold structure's trenches. This local differentiation allows the structure to maintain both high integration density and reliability by optimizing trench coverage in different areas.
2Quantity of substance
If three-dimensional mold structures are used to increase integration density, then the storage capacity is improved, but the dispersion and etching uniformity deteriorate due to the leaning phenomenon
Solution Approach 1:
By completely cutting the first mold structure into separate blocks using block trenches, the structure prevents leaning-induced etching non-uniformity from propagating across the entire device. Each block can be processed with consistent etching parameters, maintaining manufacturing precision despite the three-dimensional architecture.
Solution Approach 2:
The second mold structure implements partial block trenches that strategically expose portions of the first mold structure's trenches. This local quality variation optimizes both dispersion of processing effects and etching uniformity by creating controlled access points while maintaining structural integrity in other regions.
3Reliability
If blocks are completely separated by block trenches to improve reliability, then the product reliability is improved, but the device complexity increases
Solution Approach 1:
The first mold structure is completely segmented into blocks by block trenches, providing reliable isolation. The second mold structure uses partial segmentation with block trenches that only partially cut through, reducing the number of trenches needed while maintaining the reliability benefits of block separation.
Solution Approach 2:
The block trench system merges the functions of complete separation (in the first mold structure) with partial separation (in the second mold structure). This combined approach achieves reliability through isolation while reducing overall structural complexity by eliminating redundant trenches in the second mold structure where complete separation is not necessary.
Data Source
AI summary
A nonvolatile memory device with improved product reliability and a method of fabricating the same is provided. The nonvolatile memory device comprises a substrate, a first mold structure disposed on the substrate and including a plurality of first gate electrodes, a second mold structure disposed on the first mold structure and including a plurality of second gate electrodes and a plurality of channel structures intersecting the first gate electrodes and the second gate electrodes by penetrating the first and second mold structures, wherein the first mold structure includes first and second stacks, which are spaced apart from each other, and the second mold structure includes a third stack, which is stacked on the first stack, a fourth stack, which is stacked on the second stack, and first connecting parts, which connect the third and fourth stacks.