3D Memory Hole Cap Structure to Block Sacrificial Film Contamination
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Solution Overview
Problem
In the formation of three-dimensional memory cell arrays in semiconductor storage devices, sacrificial films with seams or voids can lead to unintended materials remaining in memory holes, potentially affecting device performance.
Innovation Solution
The use of cap films made of materials with higher density or etching selectivity to prevent materials from entering and remaining in memory holes, even in the presence of seams or voids during the formation of pillar portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a sacrificial film is embedded in memory holes to form a stacked structure, then the stacked structure can be formed, but seams or voids in the sacrificial film can cause unintended materials to remain in the memory holes
Solution Approach 1:
A cap film is introduced as an intermediary layer between the sacrificial film and the memory hole opening. This cap film seals the top surface of the sacrificial film, preventing unintended materials from entering through seams or voids in the sacrificial film during subsequent manufacturing processes.
Solution Approach 2:
The cap film is formed on the sacrificial film before any materials that could potentially contaminate the memory holes are deposited or introduced. This preliminary sealing action ensures that even if the sacrificial film has defects, the memory holes remain protected from contamination.
2Device complexity
If the sacrificial film has seams or voids, then material entry is facilitated, but preventing material retention requires additional protective measures
Solution Approach 1:
The cap film serves as a protective intermediary that compensates for the inherent imperfections in the sacrificial film structure. By placing this additional layer on top of the sacrificial film, the system prevents material entry without requiring the sacrificial film itself to be perfectly defect-free.
Solution Approach 2:
The invention changes the physical parameters of the memory hole structure by adding a cap film layer with specific properties (higher density or etching selectivity). This parameter change creates a barrier that prevents material retention even when the underlying sacrificial film has structural imperfections.
3Reliability
If cap films with higher density or etching selectivity are used, then material ingress is prevented, but the manufacturing process becomes more complex
Solution Approach 1:
The cap film is designed with specific parameter characteristics (higher density or etching selectivity compared to the sacrificial film). These parameter changes enable the cap film to effectively prevent material ingress while maintaining compatibility with existing manufacturing processes through selective deposition and etching techniques.
Data Source
AI summary
A memory includes a stacked body including electrode layers and first insulating layers stacked in a first direction. Each of a plurality of first columnar bodies includes a semiconductor layer located to penetrate through the stacked body in the first direction. A source is connected to an end part of the semiconductor layer on a side of one end of the semiconductor layer. A pillar portion is located to extend in the first direction in the stacked body, or in a structure located alongside the stacked body in a second direction, and includes a carbon material. A cap portion is located at an end part of the pillar portion on a side of another end out of one end and another end of the pillar portion respectively corresponding to the one end and another end of the semiconductor layer, and includes a first material having an etching-selectivity to the carbon material and the first insulating films.