Dielectric Support Pillars in 3D NAND Memory
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Solution Overview
Problem
Current three-dimensional memory devices face challenges in scaling support pillar structures due to the risk of electrical shorts and particle generation during the formation of stepped surfaces, particularly with sacrificial semiconductor materials like amorphous silicon, which complicates the processing and limits the scalability of these devices.
Innovation Solution
The implementation of dielectric support pillars that do not include semiconductor material, thereby avoiding the risks of electrical shorts and particle generation, and are formed in conjunction with semiconductor channels and memory films to reduce processing costs, while also allowing for the formation of monolithic three-dimensional NAND string memory devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sacrificial semiconductor material is used to form support pillar structures, then the support pillars can be formed concurrently with semiconductor channels, but electrical shorts and particle generation occur during stepped surface formation
Solution Approach 1:
The patent extracts the harmful semiconductor material from the support pillar structure, retaining only the dielectric material. This allows the support pillars to provide structural support without the risk of electrical shorts or particle generation, while still enabling concurrent formation with memory structures through the same patterning processes.
Solution Approach 2:
The patent uses a dielectric material that serves as a temporary support structure during fabrication, similar to the concept of disposable sacrificial materials. The dielectric support pillars are formed concurrently with memory structures and then removed after serving their structural purpose, avoiding the long-term reliability issues of leaving semiconductor material in place.
2Ease of manufacture
If sacrificial semiconductor material is used to form support pillars, then structural support is provided during fabrication, but particle generation occurs during processing
Solution Approach 1:
The patent removes the semiconductor material component from the support pillar structure, keeping only the dielectric material. This extraction eliminates the source of particle generation while preserving the structural support function during fabrication, as the dielectric material provides the necessary mechanical support without the contamination risks associated with semiconductor materials.
3Reliability
If dielectric support pillars are used instead of semiconductor material, then electrical shorts and particle generation are avoided, but additional processing steps are required
Solution Approach 1:
The patent merges the formation of dielectric support pillars with the existing memory structure fabrication process. The same alternating stacks of insulating and conductive layers serve dual purposes: as memory structures and as templates for forming the dielectric support pillars. This integration minimizes additional processing steps while ensuring reliable electrical isolation.
4Object-generated harmful factors
If dielectric support pillars are used instead of semiconductor material, then particle generation is avoided, but the support pillars lack the electrical properties of semiconductor material
Solution Approach 1:
The patent extracts only the structural support function from the support pillar requirement, removing the need for electrical properties. The dielectric material adequately provides mechanical support during fabrication without the contamination risks of semiconductor materials, and the electrical functionality is instead provided by the memory structures themselves.
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 enables the scalable formation of three-dimensional memory devices with dielectric support pillars that prevent electrical shorts and particle generation, facilitating the creation of monolithic three-dimensional NAND string memory devices with improved processing efficiency.
Implementation Method 1
forming at least one alternating stack of insulating layers and spacer material layers over a substrate including a semiconductor material layer, wherein the spacer material layers are formed as, or are subsequently replaced with, electrically conductive layers
Implementation Method 2
forming a first semiconductor oxide liner at a bottom portion of the support opening and a second semiconductor oxide liner at a bottom portion of the memory opening by oxidation of surface portions of the semiconductor material layer around bottom regions of the support opening and the memory opening
Implementation Method 3
forming a semiconductor material portion in contact with the semiconductor material layer in the memory opening by performing a selective semiconductor deposition process without growing any semiconductor material from the first semiconductor oxide liner
Data Source
AI summary
A semiconductor device includes an alternating stack of insulating layers and electrically conductive layers located over a substrate including a semiconductor material layer, a memory opening and a support opening extending through the alternating stack, a memory opening fill structure located in the memory opening and including a memory film and a semiconductor material portion in contact with the semiconductor material layer, and a support pillar structure located in the support opening. The support pillar structure lacks a semiconductor material portion which is in contact with the semiconductor material layer.