Phosphorus-Containing Insulator for NAND Flash Etching
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Solution Overview
Problem
In the manufacturing of nonvolatile memory devices like NAND flash with three-dimensional memory cell arrays, existing methods face challenges in efficiently forming conductive layers and insulating layers, leading to defects and reduced storage density due to the deposition of phosphorus-containing silica on insulating layers during the etching process.
Innovation Solution
The introduction of slits with a phosphorus-containing insulator in the interlayer dielectric film, which allows for the deposition of phosphorus-containing silica on the inner walls of these slits, reducing its deposition on adjacent insulating layers and enabling easier embedding of conductive materials like tungsten, thereby increasing storage density and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If phosphorus-containing silica is deposited during the etching process, then etching efficiency is improved, but deposition on insulating layers causes defects and reduces storage density
Solution Approach 1:
A phosphorus-containing insulator layer is introduced as an intermediary between the etching process and the insulating layers. This mediator layer selectively absorbs phosphorus-containing silica deposition, protecting the insulating layers from contamination while allowing the etching process to proceed efficiently. The mediator layer is positioned at specific regions where deposition occurs, acting as a sacrificial barrier that can be removed or retained based on process requirements.
Solution Approach 2:
The phosphorus-containing insulator is applied locally to specific regions rather than uniformly across all insulating layers. This localized application targets areas where phosphorus-containing silica deposition is most problematic during etching, allowing the insulating layers in non-critical regions to remain unaffected. The local quality approach enables selective protection where needed while maintaining storage density in other areas.
2Manufacturing precision
If insulating layers are stacked densely to increase storage density, then storage capacity increases, but the distance between layers narrows making conductive material embedding difficult
Solution Approach 1:
The phosphorus-containing insulator serves as a mediator that facilitates conductive material embedding between densely stacked insulating layers. By controlling the deposition and removal of this insulator layer, the process enables precise positioning of conductive materials like tungsten in narrow spaces without causing short-circuits. The intermediary layer provides a controlled interface that guides material deposition and prevents unwanted bridging between adjacent insulating layers.
Solution Approach 2:
The distance and physical properties of the phosphorus-containing insulator layer are dynamically adjusted during the manufacturing process. By controlling the thickness, composition, and removal timing of this layer, the process adapts to maintain optimal spacing for conductive material embedding even when insulating layers are densely stacked. Parameter changes in the insulator layer enable flexible control over the embedding process throughout production.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the deposition efficiency of phosphorus-containing silica, allowing for increased density of word lines and improved storage capacity by minimizing the narrowing of insulating layer distances and preventing short-circuiting, while maintaining the functionality of the semiconductor storage device.
Implementation Method 1
allows for the deposition of phosphorus-containing silica on the inner walls of these slits
Data Source
AI summary
A semiconductor storage device according to an embodiment comprises a substrate. A stack body having first conductive layers and first insulating layers alternately stacked in a first direction is provided on the substrate. A pillar part extends in the first direction in the stack body and has a memory film. An insulating member extends in the first direction at a position different from that of the pillar part in the stack body. A phosphorus-containing insulator is provided below the stack body and the insulating member.