Staircase Portion Width Reduction in 3D Memory Devices
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Solution Overview
Problem
The downscaling of memory devices is impeded by the large planar size of the staircase portion in three-dimensional semiconductor devices, which is necessary for supporting dummy posts during the replacement of sacrificial layers with electrode layers.
Innovation Solution
The semiconductor device incorporates a staircase portion with a first and second separation region, where the second portion has a narrower width than the first, allowing the use of insulator-filled regions as support walls instead of dummy posts, reducing the planar surface area and enabling smaller dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dummy posts are provided in the terraces to support the stacked body during replacement of sacrificial layers with electrode layers, then the stability and reliability of the replacement process is improved, but the planar size of the staircase portion increases
Solution Approach 1:
The invention extracts and removes the dummy posts from the staircase portion entirely. Instead of providing dummy posts in the terraces, the patent uses the insulating bodies themselves as support structures during the replacement process, eliminating the need for separate dummy post elements and thereby reducing the planar size of the staircase portion.
Solution Approach 2:
The insulating bodies serve multiple functions: they act as both the structural components of the stacked body and as support walls during the replacement of sacrificial layers with electrode layers. This multi-functionality eliminates the need for separate dummy posts while maintaining the stability required for the replacement process.
2Area of stationary object
If the planar size of the terrace is reduced to enable downscaling of the memory device, then the area occupied by the staircase portion is reduced, but the ability to provide dummy posts for support is compromised
Solution Approach 1:
The invention removes the dummy posts from the design, extracting their support function and transferring it to the insulating bodies themselves. This allows for reduced planar size while maintaining support capability during the replacement process.
Solution Approach 2:
The insulating bodies serve themselves as support structures during the replacement process. Instead of requiring external dummy posts, the insulating bodies inherently provide the necessary support walls, enabling the system to support itself during manufacturing operations.
Data Source
AI summary
A semiconductor device includes a stacked body including a plurality of electrode layers stacked with an insulator interposed; a columnar portion provided in the stacked body and extending in a stacking direction of the electrode layers; and a first separation region provided in the stacked body and extending in a first direction. The stacked body includes a memory cell array and a staircase portion arranged in the first direction, the memory cell array including memory cells provided along the columnar portion, and the staircase portion including a plurality of terraces arranged along the first direction. The first separation region includes a first portion and a second portion in the staircase portion, the first portion having a first width in a second direction crossing the first direction, and the second portion having a second width in the second direction. The second width is narrower than the first width.