3D Memory Stacked Body Collapse Prevention via Pedestal Support
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Solution Overview
Problem
In semiconductor devices with a three-dimensional stacked structure, the replacement of sacrificial films with semiconductor layers can lead to the collapse of the stacked body, particularly due to the narrowing of insulators in columnar portions, which affects the structural integrity and functionality.
Innovation Solution
Incorporating a first pedestal portion and second columnar portions with specific insulator configurations, including silicon oxide, to prevent the narrowing of insulators and maintain structural stability during the replacement process, thereby suppressing the collapse of the stacked body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a sacrificial film is replaced with a semiconductor layer to form the source region, then the source formation is achieved, but the stacked body may collapse due to insulator narrowing
Solution Approach 1:
A pedestal structure is formed in advance at the lower portion of the stacked body before the sacrificial film replacement process. This pedestal acts as a support structure that prevents the stacked body from collapsing during and after the sacrificial film is replaced with semiconductor material to form the source region.
Solution Approach 2:
The pedestal structure serves as an intermediary support element between the substrate and the stacked body. It provides mechanical support during the critical replacement process, allowing the sacrificial film to be removed and replaced with semiconductor material without causing the stacked body to collapse.
2Stability of the object's composition
If the stacked body structure is maintained, then structural integrity is preserved, but downscaling of the device is limited
Solution Approach 1:
The support structure is segmented into a pedestal portion located at the lower region of the stacked body, separating the support function from the memory cell structure. This segmentation allows the stacked body to be scaled down while maintaining structural integrity through the dedicated pedestal support.
Solution Approach 2:
The pedestal structure provides localized support at the lower portion of the stacked body where it is most needed during the replacement process. This local reinforcement allows overall device downscaling while maintaining structural integrity at the critical support point.
Data Source
AI summary
A semiconductor device includes a base body portion, a stacked body, a pedestal portion, a plate portion, and first and second columnar portions. The base body portion includes a doped semiconductor film and a semiconductor portion. The doped semiconductor film includes first and second portions. The semiconductor portion includes a first region overlapping the first portion, and a second region overlapping the second portion and being a body different from the first region. The pedestal portion is provided in the second region. The plate portion contacts the pedestal portion and the first region. The first columnar portion includes a semiconductor layer. The semiconductor layer is adjacent to the plate portion with the stacked body interposed, and contacts the first region. The second columnar portion is adjacent to the plate portion with the stacked body interposed, and is adjacent to the pedestal portion with the second region interposed.