Vertical Memory Stepped Word Line Formation
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Solution Overview
Problem
The existing methods for manufacturing vertical-type semiconductor devices require complex photolithography and etching processes to form stepped shape word lines, leading to increased processing costs and potential defects.
Innovation Solution
A method involving the stacking of sacrificial and insulating layers on a substrate, forming a preliminary stepped shape pattern structure, and then creating pillar structures and gaps to form word lines and selection lines through simplified etching and filling processes, reducing the number of necessary steps and potential defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithography and etching processes are used to form stepped shape word lines, then precise stepped patterns can be achieved, but processing complexity and costs increase significantly
Solution Approach 1:
The patent applies preliminary action by pre-forming sacrificial layers (nitride layers) at specific positions before depositing the insulating layers. These sacrificial layers serve as placeholders that automatically create the stepped configuration when subsequently removed. This preliminary placement of sacrificial materials eliminates the need for complex photolithography patterning steps to create the stepped shape, as the steps emerge naturally from the sacrificial layer removal process.
Solution Approach 2:
The patent uses sacrificial layers as intermediary materials that facilitate the formation of stepped patterns without requiring direct patterning of the final word line structure. These intermediary nitride layers are deposited, patterned once, and then removed after serving their purpose of defining the stepped geometry. This intermediary approach simplifies the overall process by replacing multiple photolithography-etch cycles with a single sacrificial layer deposition and removal sequence.
2Manufacturing precision
If multiple photolithography and etching processes are conducted to form stepped word lines, then precise wiring connections can be achieved, but processing time and production costs increase
Solution Approach 1:
The patent merges multiple patterning operations into a single unified process. Instead of performing separate photolithography and etching steps for each level of the stepped structure, the method combines all stepped pattern formation into one process sequence: deposit sacrificial layers at desired positions, deposit insulating layers over them, then remove the sacrificial layers in a single etching step. This merging of operations dramatically reduces processing time while maintaining wiring connection precision through the controlled deposition and removal sequences.
Solution Approach 2:
The preliminary placement of sacrificial layers establishes the complete stepped geometry blueprint before any insulating materials are deposited. This preliminary action ensures that when the sacrificial layers are removed, the precise stepped wiring connections are automatically formed without requiring subsequent re-patterning or adjustment steps, thereby reducing total processing time while preserving connection accuracy.
3Reliability
If conventional stepped shape formation methods are used, then proper electrical connections can be established, but the number of process steps and potential defects increase
Solution Approach 1:
The sacrificial layers act as intermediaries that temporarily hold the stepped structure definition during fabrication. By using these intermediary nitride layers, the process achieves reliable electrical connections through a simplified sequence: deposit sacrificial layers, deposit insulating layers conformally over them, then remove sacrificial layers to reveal the stepped configuration. This intermediary approach reduces the total number of process steps compared to conventional methods while maintaining connection reliability through controlled deposition and removal.
Solution Approach 2:
The patent employs the discarding and recovering principle by using sacrificial layers that are intentionally deposited, serve their structural definition purpose, and then completely removed after transferring their pattern information to the insulating layers. These discarded sacrificial materials enable the formation of reliable stepped connections without requiring the final structure to retain them, thereby simplifying the process by eliminating the need for additional patterning steps to achieve the same result.
Data Source
AI summary
A method of manufacturing a vertical type memory device includes stacking a first lower insulating layer, one layer of a lower sacrificial layer and a second lower insulating layer on a substrate, forming a stacking structure by stacking sacrificial layers and insulating layers, and etching an edge portion of the stacking structure to form a preliminary stepped shape pattern structure. The preliminary stepped shape pattern structure has a stepped shape edge portion. A pillar structure making contact with a surface of the substrate is formed. The preliminary stepped shape pattern structure, the lower sacrificial layer, and the first and second lower insulating layers are partially etched to form a first opening portion and a second opening portion to form a stepped shape pattern structure. The second opening portion cuts at least an edge portion of the lower sacrificial layer.