3D Memory Cell Column Structure to Prevent Stack Collapse
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Solution Overview
Problem
The collapse of the stacked body during the replacement of sacrificial films with semiconductor layers in nonvolatile memory devices is a challenge, particularly as the technology scales down, leading to reduced manufacturing yield and stability issues.
Innovation Solution
The semiconductor device design includes first and second columnar parts with varying diameters within the semiconductor parts to provide structural support, ensuring the stacked body remains stable during the replacement process by maintaining a wider diameter within the semiconductor parts, thereby preventing collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the stacked body is scaled down to increase memory density, then productivity and memory capacity are improved, but the stacked body becomes more prone to collapse during manufacturing
Solution Approach 1:
The stacked body is divided into multiple finger-like structures extending in the first direction, with each finger being a separate structural unit. This segmentation reduces the overall footprint while maintaining structural integrity through distributed support, preventing collapse during manufacturing processes.
Solution Approach 2:
Different regions of the stacked body have different structural characteristics - the finger-like structures provide localized support in critical areas while allowing other regions to be optimized for memory cell density. This local differentiation maintains stability where needed while maximizing storage capacity elsewhere.
2Adaptability or versatility
If sacrificial films are replaced with semiconductor layers to form source regions, then device functionality is improved, but the stacked body collapses during the replacement process
Solution Approach 1:
The finger-like structures are formed in advance before the sacrificial film replacement process. These pre-formed structures provide structural support throughout the subsequent manufacturing steps, preventing collapse when sacrificial films are removed and replaced with semiconductor layers.
Solution Approach 2:
The finger-like structures act as intermediary support elements between the stacked body and the underlying substrate. They provide mechanical support during the sacrificial film replacement process, enabling the removal and replacement operations to proceed without causing structural collapse.
3Productivity
If the diameter of columnar parts is reduced to increase memory cell density, then productivity is improved, but structural support is insufficient leading to collapse
Solution Approach 1:
Instead of increasing the diameter of individual columnar parts (one-dimensional approach), the invention extends structures in the first direction (horizontal dimension) to create finger-like formations. This dimensional change provides structural support without compromising the vertical density of memory cells.
Solution Approach 2:
The support structure is segmented into multiple finger-like units rather than using a single thick columnar structure. This segmentation distributes the structural support function across multiple elements, providing adequate strength while maintaining small individual dimensions that allow high memory cell density.
Data Source
AI summary
A semiconductor device includes a base body, a stacked body on the base body and a first columnar part. The base body includes a substrate, a first insulating film on the substrate, a first conductive film on the first insulating film, and a first semiconductor part on the first conductive film. The stacked body includes conductive layers and insulating layers stacked alternately in a stacking direction. The first columnar part is provided inside the stacked body and the first semiconductor part. The first columnar part includes a semiconductor body and a memory film between the semiconductor body and conductive layers. The semiconductor body extends in the stacking direction. The first columnar part has a first diameter and a second diameter in a first direction crossing the stacking direction. The first diameter inside the first semiconductor part is larger than the second diameter inside the stacked body.