3D Memory Stairway Structure for High-Density Cell Isolation
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Solution Overview
Problem
Two-dimensional semiconductor memory devices face limitations due to increased interference between memory cells as line widths narrow, leading to performance degradation and higher manufacturing costs.
Innovation Solution
A three-dimensional memory device is proposed, featuring first and second isolation patterns, a stack with a connection region and insulating region, and stairway-shaped recesses to enhance integration and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If line width is narrowed to increase integration density, then storage capacity per area is improved, but interference between memory cells increases causing performance degradation
Solution Approach 1:
The patent transitions from a two-dimensional planar structure to a three-dimensional structure by introducing vertical stacking of memory cells. Multiple memory cell stacks are arranged vertically above the substrate, allowing increased storage capacity without narrowing line widths in the planar direction. This dimensional change eliminates cell interference issues while achieving higher integration density.
2Quantity of substance
If line width is narrowed to increase integration density, then storage capacity per area is improved, but manufacturing cost increases due to expensive equipment
Solution Approach 1:
By stacking memory cells vertically in the third dimension, the patent achieves higher storage capacity without requiring finer planar patterning. This avoids the need for expensive narrow-line-width lithography equipment, as the integration density improvement comes from vertical stacking rather than horizontal line width reduction.
3Quantity of substance
If memory cells are stacked vertically to increase capacity, then storage capacity per area is improved, but device structure becomes more complex
Solution Approach 1:
The memory device is segmented into multiple identical memory cell stacks arranged vertically. Each stack is a self-contained unit with standardized structure including channel regions, gate electrodes, and insulating layers. This modular segmentation allows complex 3D functionality to be achieved through repetition of standardized building blocks, managing structural complexity through modularity.
Solution Approach 2:
The patent implements nested structures where gate electrodes and insulating layers are arranged in concentric or alternating patterns around channel regions. Multiple gate electrodes are nested vertically around channel regions at different heights, creating a compact three-dimensional configuration that maximizes space utilization while maintaining structural organization.
Data Source
AI summary
A three-dimensional memory device includes first and second isolation patterns extending in a first direction, and adjacent to each other in a second direction intersecting with the first direction; a stack disposed between the first isolation pattern and the second isolation pattern, and including a connection region including a plurality of electrode layers and a plurality of interlayer insulating layers alternately stacked in a vertical direction and an insulating region surrounded by the connection region; and a plurality of stairway-shaped recesses configured in the insulating region and the connecting region, and arranged in the first direction, wherein at least one of the plurality of stairway-shaped recesses comprises a first stairway structure connected to the first isolation pattern, a second stairway structure connected to the second isolation pattern, and a sidewall connecting the first stairway structure and the second stairway structure and disposed in the insulating region.