3D Semiconductor Memory Stacked Gate Vertical Channel Integration
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Solution Overview
Problem
The integration density of semiconductor memory devices is limited by their available planar area, hindering cost savings and performance improvements.
Innovation Solution
The development of three-dimensional semiconductor memory devices with a gate structure featuring alternately stacked gate and insulating patterns, vertical active patterns, and semiconductor patterns, including a string drain region spaced apart from the vertical active patterns to maintain channel region integrity and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If three-dimensional semiconductor memory devices are developed to increase integration density, then the integration density and performance are improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent transitions from planar two-dimensional memory architecture to three-dimensional vertical architecture by stacking multiple gate patterns (first through fourth gate patterns) and active patterns in the vertical dimension. This enables higher integration density by utilizing the third dimension (depth) rather than only the planar surface area, allowing multiple memory cells to be stacked vertically within the same footprint.
Solution Approach 2:
The patent implements a nested structure where multiple gate patterns and active patterns are stacked vertically, with each layer containing memory cells that are interconnected through vertical channels. The string drain region is positioned to receive signals from multiple vertically stacked memory cell strings, creating a nested configuration where higher-level components aggregate signals from lower-level components.
2Area of stationary object
If string drain region is positioned closer to vertical active pattern to reduce area, then planar area is saved, but dopant interference increases and reliability decreases
Solution Approach 1:
The patent resolves the spatial conflict between string drain region and vertical active pattern by transitioning from planar positioning to vertical stacking. The string drain region is positioned at a higher vertical level than the vertical active patterns, allowing both components to coexist without planar overlap while maintaining appropriate spacing to prevent dopant interference. This vertical separation preserves channel region stability while efficiently utilizing three-dimensional space.
3Quantity of substance
If more gate patterns are stacked to increase memory capacity, then integration density improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent divides the memory device into multiple discrete gate patterns (first, second, third, and fourth gate patterns) that are stacked vertically. Each gate pattern can be formed and positioned as a separate manufacturing unit, allowing for modular fabrication. This segmentation enables incremental assembly and alignment, reducing the overall manufacturing precision burden compared to forming all layers in a single complex process.
Solution Approach 2:
The patent introduces insulating patterns as intermediary layers between the gate patterns. These insulating patterns serve as spacing elements and alignment references that facilitate precise positioning of adjacent gate patterns during manufacturing. The insulating patterns act as mediators that maintain consistent vertical spacing and provide physical references for alignment, thereby reducing the precision requirements for direct gate-to-gate alignment.
Data Source
AI summary
Three-dimensional (3D) semiconductor memory devices are provided. According to the 3D semiconductor memory device, a gate structure includes gate patterns and insulating patterns alternately stacked on a semiconductor substrate. A vertical active pattern penetrates the gate structure. A gate dielectric layer is disposed between a sidewall of the vertical active pattern and each of the gate patterns. A semiconductor pattern is disposed on the gate structure and is connected to the vertical active pattern. A string drain region is formed in a portion of the semiconductor pattern and is spaced apart from the vertical active pattern.