3D Memory Stack Layout With Dummy Structures Against Warpage
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Solution Overview
Problem
Existing semiconductor devices face challenges in increasing data storage capacity and maintaining reliability, particularly in three-dimensional memory cell structures.
Innovation Solution
The semiconductor device incorporates a memory cell region with a memory stack structure and a dummy structure, featuring alternating insulating layers and gate electrodes, channel structures, and separation structures that extend in different directions to enhance structural integrity and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory cells are arranged three-dimensionally to increase data storage capacity, then storage capacity is improved, but structural stability deteriorates due to warpage during manufacturing and packaging
Solution Approach 1:
The patent introduces dummy stack structures that replicate the physical form and material composition of actual memory stacks without containing functional channel structures. These dummy stacks are positioned adjacent to real stacks to mimic their thermal expansion and warpage characteristics, thereby providing structural compensation. The dummy stacks are formed with the same alternating layers of insulating materials and gate electrodes as functional stacks, creating identical mechanical properties for warpage compensation purposes.
Solution Approach 2:
The patent modifies the physical and material parameters of the dummy stack structures to match those of functional memory stacks. This includes using the same insulating layer materials (e.g., silicon oxide, silicon nitride), the same gate electrode materials, and the same layer thicknesses. By matching these parameters, the dummy stacks exhibit identical thermal and mechanical behavior, enabling them to compensate for warpage in the three-dimensional memory array during manufacturing and packaging processes.
2Reliability
If separation structures are added to enhance structural integrity, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent divides the three-dimensional memory structure into discrete segments by introducing separation structures between adjacent memory stacks and between dummy stacks. These separation structures physically partition the continuous stack array into isolated units, preventing stress propagation and reducing mutual interference between neighboring stacks. The segmentation is achieved through etching separation trenches between stacks and filling them with insulating material, creating independent structural units that enhance overall reliability.
Solution Approach 2:
The separation structures serve as intermediary elements positioned between functional memory stacks and between dummy stacks. These intermediaries provide mechanical isolation and stress relief, acting as buffer zones that prevent warpage and structural defects from propagating across the entire memory array. The separation structures include separation trenches filled with insulating material, which mediate the mechanical interactions between adjacent stacks and improve structural integrity.
Data Source
AI summary
A semiconductor device includes a memory cell structure on a substrate, and a dummy structure on a side of the memory cell structure. The memory cell structure includes a memory stack structure including interlayer insulating layers and gate electrodes alternately stacked on the substrate, channel structures penetrating through the memory stack structure and contacting the substrate, and first separation structures penetrating through the memory stack structure and extending in the first direction to separate the gate electrodes from each other in a second direction. The dummy structure includes dummy stack structures spaced apart from the memory stack structure and including first insulating layers and dummy gate electrodes alternately stacked, dummy channel structures penetrating through the dummy stack structures, and second separation structures penetrating through the dummy stack structures and extending in the second direction to separate the dummy gate electrodes from each other in the first direction.