3D Memory Staircase Electrodes With Air Gaps And Columnar Supports
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Solution Overview
Problem
The existing three-dimensional memory device manufacturing methods face challenges in efficiently forming staircase-shaped electrode layers and supporting structures, which can lead to interference with the semiconductor body and hinder the formation of air gaps between electrode layers, affecting the device's operational efficiency and charge retention characteristics.
Innovation Solution
The semiconductor device incorporates a stacked body with columnar parts and insulating layers, where the electrode layers are formed in a staircase shape with air gaps, supported by columnar parts, and contact vias are used to connect these layers to a control circuit, ensuring proper alignment and reduced interference, while the second columnar parts with varying lengths support the electrode layers in the staircase section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electrode layers are processed in a staircase shape to connect to control circuits, then ease of operation is improved, but the contact via may interfere with the semiconductor body of the columnar part
Solution Approach 1:
The columnar parts are divided into first columnar parts (with semiconductor bodies) and second columnar parts (without semiconductor bodies). The second columnar parts are specifically positioned to support the staircase-shaped electrode layers, separating the support function from the memory storage function and preventing interference with semiconductor bodies.
Solution Approach 2:
Second columnar parts act as intermediary support structures between the staircase-shaped electrode layers and the substrate. These intermediate supports enable the staircase configuration without requiring contact vias to directly interfere with the semiconductor bodies of the first columnar parts.
2Reliability
If air gaps are formed between electrode layers to reduce interconnect capacitance, then operational efficiency is improved, but the stacked body requires support structures that increase device complexity
Solution Approach 1:
The second columnar parts serve multiple functions: they support the stacked body structure, maintain the air gaps between electrode layers, and provide structural stability for the staircase-shaped electrode layers. This multi-functionality reduces the need for additional dedicated support structures.
Solution Approach 2:
The support function for the air-gapped electrode layers is merged into the columnar part structure itself. By making some columnar parts (second columnar parts) consist solely of insulating films without semiconductor bodies, the support function is integrated into the existing vertical structure rather than requiring separate support elements.
3Ease of operation
If second columnar parts with varying lengths are used to support staircase electrode layers, then ease of operation is improved, but manufacturing precision requirements increase
Solution Approach 1:
The second columnar parts with varying lengths are formed in advance during the stacking process, creating predetermined support positions for the staircase-shaped electrode layers. This preliminary structuring guides subsequent processing steps and simplifies the alignment of contact vias to specific electrode layer ends.
Data Source
AI summary
According to one embodiment, the plurality of contact vias extend in the stacking direction in the insulating layer, and are in contact with the end parts of the electrode layers. The plurality of second columnar parts extend in the stacking direction in the second stacked part, and include a plurality of second semiconductor bodies being different in length in the stacking direction.