3D Memory Stack Bridge Structure Against Replacement Collapse
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Solution Overview
Problem
Three-dimensional memory devices face challenges in preventing stack collapse during replacement processes due to lack of adequate structural support, which affects the reliability and durability of the memory devices.
Innovation Solution
The implementation of a three-dimensional memory device structure that includes alternating stacks of word lines and insulating layers, memory stack structures, backside trench fill structures, and bridge regions with continuous insulating layers extending through these structures, providing enhanced structural support and preventing stack collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If traditional three-dimensional memory device structures are used without additional support structures, then the device complexity is reduced and manufacturing is easier, but the structural integrity deteriorates and stack collapse occurs during replacement processes
Solution Approach 1:
The patent introduces bridge structures as intermediary elements between the memory stacks and substrate. These bridges serve as mediator support structures that prevent stack collapse during replacement processes while maintaining the overall device architecture. The bridges are formed as separate structural elements that span between trenches, providing mechanical support without directly modifying the memory stack structures themselves.
Solution Approach 2:
The patent segments the support function from the memory storage function by introducing separate bridge structures. Instead of making the memory stacks themselves more robust, the support function is divided into distinct bridge elements that can be independently formed and optimized. This segmentation allows the memory structures to remain simple while gaining external support.
2Reliability
If bridge structures are added to prevent stack collapse, then structural integrity is improved, but the manufacturing process becomes more complex and time-consuming
Solution Approach 1:
The bridge structures are formed preliminarily before the replacement process occurs. By pre-forming the bridges and filling the trenches with dielectric material before introducing the replacement structure, the patent ensures structural support is in place beforehand, preventing collapse during subsequent processing steps. This preliminary action eliminates the need for complex in-situ support mechanisms.
Solution Approach 2:
The bridge structures function as temporary support elements that serve their purpose during the replacement process and can be removed or left as part of the final structure. They are relatively simple dielectric or conductive structures that provide necessary mechanical support without requiring long-term functionality, analogous to disposable support elements in manufacturing.
3Strength
If continuous insulating layers extend through bridge regions, then structural support is enhanced and stack collapse is prevented, but the manufacturing precision requirements increase
Solution Approach 1:
The continuous insulating layer is implemented specifically in the bridge regions where structural support is needed, rather than uniformly throughout the entire device. This local quality approach provides enhanced structural support precisely where the stacks are most vulnerable to collapse during replacement processes, while minimizing the overall impact on manufacturing complexity.
Data Source
AI summary
A three-dimensional memory device includes a first alternating stack of first word lines and first insulating layers, first memory stack structures vertically extending through the first alternating stack, a second alternating stack of second word lines and second insulating layers, second memory stack structures vertically extending through the second alternating stack, plural backside trench fill structures located between the first alternating stack and the second alternating stack, and a bridge region located between the plural backside trench fill structures and between the between the first alternating stack and the second alternating stack. At least one insulating layer extends continuously through the first alternating stack, the second alternating stack, and the bridge region.