3D Semiconductor Stack Layout for Dense Memory Cell Integration
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Solution Overview
Problem
Conventional two-dimensional semiconductor devices face limitations in integration density due to the high cost and complexity of forming fine patterns, which restricts their performance and manufacturing efficiency.
Innovation Solution
A three-dimensional semiconductor device architecture is developed, featuring a stack structure with vertically stacked electrodes and insulating layers, and a connection region with stepwise structures that allow for increased integration density by reducing the distance each stack extends into the connection region, enabling better filling of insulation layers and improved contact plug connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional two-dimensional semiconductor devices are used, then manufacturing processes are simpler, but integration density is limited
Solution Approach 1:
The patent transitions from conventional two-dimensional planar semiconductor devices to three-dimensional vertically stacked structures. Multiple memory cells are stacked vertically along the third dimension, enabling significantly higher integration density without requiring finer lateral patterning. The stack structure includes alternating layers of first and second electrodes with insulating layers between them, forming multiple functional cells in the vertical direction.
2Manufacturing precision
If fine patterns are formed to increase integration density, then integration density improves, but manufacturing cost increases
Solution Approach 1:
Instead of increasing integration density through finer lateral patterning which requires extremely high-priced apparatuses, the patent achieves higher density by stacking multiple memory cells vertically. This dimensional transition allows use of relatively coarser lateral patterns while maintaining high integration density, thereby reducing manufacturing cost.
Solution Approach 2:
Multiple memory cells are nested vertically within a single footprint area. Each stack contains multiple alternating electrode layers that form multiple functional memory cells, effectively nesting functional units one above another to maximize space utilization without requiring proportionally finer patterning.
3Reliability
If stacks extend further into the connection region, then connectivity is improved, but insulation layer filling becomes less efficient
Solution Approach 1:
The patent applies different horizontal spacing between electrodes at different vertical levels. In the connection region where contact plugs are formed, a first distance is maintained between second electrodes of adjacent stacks. In the cell array region, a smaller second distance is maintained between first and second electrodes. This local variation optimizes both connectivity in the connection region and insulation layer filling efficiency in the cell array region.
Data Source
AI summary
A three-dimensional (3D) semiconductor device includes a stack structure including first and second stacks stacked on a substrate. Each of the first and second stacks includes a first electrode and a second electrode on the first electrode. A sidewall of the second electrode of the first stack is horizontally spaced apart from a sidewall of the second electrode of the second stack by a first distance. A sidewall of the first electrode is horizontally spaced apart from the sidewall of the second electrode by a second distance in each of the first and second stacks. The second distance is smaller than a half of the first distance.