Semiconductor Storage Device Stair Portion Structural Integrity
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Solution Overview
Problem
In three-dimensional nonvolatile memory, maintaining the strength of the stacked structure is a challenge due to the fragility of the stacked body during the replacement process, particularly in the stair portion where the insulating layers are replaced with conductive layers.
Innovation Solution
The semiconductor storage device incorporates a stair portion with projections on its side surfaces, where the insulating layer continuously extends across multiple conductive layers, providing structural support and preventing bending during the replacement process, and utilizes an insulating layer to cover the end surfaces of the conductive layers and projections, enhancing the stability of the stacked structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If insulating layers are replaced with conductive layers in the stair portion, then the functionality of the memory device is improved, but the structural strength and stability of the stacked body deteriorates
Solution Approach 1:
The insulating layer is extended in advance to the side surfaces of the stair portion before the replacement process begins. This preliminary extension creates a support structure that prevents bending and maintains structural integrity during the subsequent replacement of insulating layers with conductive layers.
Solution Approach 2:
The insulating layer is divided into multiple regions: a first region covering the end surfaces of conductive layers, a second region extending to side surfaces, and a third region forming projections. This segmentation allows different portions of the insulating layer to serve different structural functions, with the second and third regions specifically providing support during replacement.
2Ease of manufacture
If the stacked body structure is simplified for easier manufacturing, then the ease of manufacture is improved, but the stability of the stacked structure during replacement deteriorates
Solution Approach 1:
The insulating layer performs multiple functions simultaneously: it provides electrical insulation, structural support during replacement, and mechanical reinforcement through projections. This multi-functionality allows a single component to address both manufacturing simplicity and structural stability requirements.
Solution Approach 2:
The insulating layer is configured with different properties in different regions: the first region provides insulation, while the second and third regions extending to and forming projections on side surfaces provide enhanced structural support. This local differentiation optimizes both manufacturability and stability.
Data Source
AI summary
According to one embodiment, a semiconductor storage device includes a stacked body that includes a plurality of first conductive layers stacked with a first insulating layer interposed therebetween and has a stair portion and a memory portion; and a first structure that extends in the stacked body in a predetermined direction and divides the stacked body, the first structure including a projection extending in the stacking direction across the plurality of first conductive layers, on a side surface thereof in the stair portion wherein the first structure includes: a second insulating layer that is provided in the projection; and a third insulating layer that covers end surfaces of the plurality of first conductive layers and the first insulating layer facing toward the first structure and continuously extends in the first structure over the memory portion and the stair portion.