3D Memory Staircase Layout With Overlapping Dummy Structure
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Solution Overview
Problem
Current semiconductor devices face challenges in increasing data storage capacity and improving integration density and reliability, particularly in three-dimensional (3D) semiconductor memory devices.
Innovation Solution
The semiconductor device architecture includes a cell array region, a dummy region, and a cell contact region with specific stack structures, vertical channel structures, and cell contact plugs, along with a dummy structure that vertically overlaps with the staircase structure, enhancing integration density and reliability through advanced manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If three-dimensionally arranged memory cells are used instead of two-dimensionally arranged memory cells, then data storage capacity is increased, but manufacturing complexity and process difficulty increase
Solution Approach 1:
The patent implements a three-dimensional memory structure by stacking multiple memory cell layers vertically above the substrate, transitioning from traditional two-dimensional planar arrangement to vertical stacking. This enables increased storage capacity by utilizing the vertical dimension, with multiple bit lines and word lines arranged in different heights to form three-dimensional memory cells.
Solution Approach 2:
The memory device is divided into multiple discrete memory cell layers, each containing complete sets of bit lines, word lines, and memory cells. This segmentation allows for modular manufacturing processes and enables the complex three-dimensional structure to be built through repeated deposition and patterning cycles for each layer.
2Quantity of substance
If three-dimensionally arranged memory cells are used instead of two-dimensionally arranged memory cells, then data storage capacity is increased, but reliability deteriorates
Solution Approach 1:
The patent incorporates dummy structures in regions adjacent to the memory cell arrays, including dummy bit lines and dummy word lines that extend beyond the active memory region. These dummy structures serve as buffer elements that compensate for stress variations and manufacturing variations, thereby maintaining device reliability in the three-dimensional configuration.
Solution Approach 2:
Different regions of the device are designed with different structural characteristics - the memory cell array region contains the functional three-dimensional memory cells, while adjacent regions contain dummy structures with modified geometries. This local differentiation allows the functional region to achieve high storage capacity while the dummy regions provide reliability enhancement through stress compensation and manufacturing tolerance buffering.
3Reliability
If dummy structures are added adjacent to the memory cell array, then reliability is improved, but area occupied increases
Solution Approach 1:
The dummy structures are positioned to vertically overlap with portions of the memory cell layers in the three-dimensional stack, allowing the dummy bit lines and word lines to occupy the same lateral footprint as some of the memory cells. This nesting arrangement enables the dummy structures to provide reliability enhancement without significantly increasing the lateral chip area, as they utilize the vertical stacking space efficiently.
Data Source
AI summary
A semiconductor device includes an upper-level layer having a cell array region, a cell contact region and a dummy region on a substrate. The upper-level layer includes a semiconductor layer, a cell array structure including first and second stack structures sequentially stacked on the semiconductor layer of the cell array region, the first and second stack structures comprising stacked electrodes, a first staircase structure on the semiconductor layer of the cell contact region, the electrodes extending from the cell array structure into the first staircase structure such that the cell array structure is connected to the first staircase structure, a vertical channel structure penetrating the cell array structure, a dummy structure in the dummy region, the dummy structure at the same level as the second stack structure, the dummy structure including stacked first layers, and cell contact plugs in the cell contact region and connected to the first staircase structure.