Selective Nitridation via Remote Plasma Radical Delivery
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Solution Overview
Problem
The nitridation process in NAND flash memory device manufacturing incorporates nitrogen into shallow trench isolation regions, creating a charge leakage path that negatively impacts device performance, necessitating improved methods for nitridation of semiconductor materials.
Innovation Solution
A remote plasma system is used to generate and deliver plasma radicals at an angle to a processing chamber, eliminating ions and selectively incorporating atomic radicals into silicon or polysilicon regions, thereby enhancing the selectivity of nitridation and reducing charge leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional nitridation process is used to incorporate nitrogen into floating gate, then reliability of tunnel oxide is improved, but nitrogen is also incorporated into shallow trench isolation regions creating charge leakage paths
Solution Approach 1:
The patent segments the nitridation process into two distinct stages: a first nitridation process that incorporates nitrogen into both the floating gate and shallow trench isolation regions, and a second nitridation process that selectively removes nitrogen from the shallow trench isolation regions while maintaining nitrogen in the floating gate. This segmentation allows the process to achieve the desired reliability improvement while eliminating the harmful charge leakage paths.
Solution Approach 2:
The patent applies the discarding and recovering principle by intentionally allowing nitrogen to be incorporated into the shallow trench isolation regions during the first nitridation process, then selectively removing (discarding) this nitrogen in the second nitridation process. This approach recovers the floating gate's nitrogen content while discarding the harmful nitrogen in the isolation regions, thereby eliminating charge leakage paths while maintaining tunnel oxide reliability.
2Stability of the object's composition
If nitridation process is used to suppress dopant diffusion, then floating gate stability is improved, but nitrogen incorporation in isolation regions forms charge leakage paths
Solution Approach 1:
The patent divides the nitridation treatment into sequential stages: initial nitridation that provides stability to the floating gate by incorporating nitrogen, followed by a selective removal process that eliminates nitrogen from isolation regions. This segmentation enables the process to maintain floating gate stability while removing the source of charge leakage paths.
Solution Approach 2:
The process recovers the beneficial nitrogen incorporation in the floating gate that provides stability and suppresses dopant diffusion, while discarding the harmful nitrogen in the shallow trench isolation regions that creates charge leakage paths. This selective retention and removal resolves the contradiction between stability improvement and harmful factor generation.
3Productivity
If conventional plasma nitridation is used, then nitrogen incorporation efficiency is high, but selectivity between different regions is poor
Solution Approach 1:
The patent segments the nitridation process into two distinct processes with different parameters: a first process optimized for high nitrogen incorporation efficiency into all regions, and a second process optimized for selective nitrogen removal from isolation regions. This segmentation enables the overall process to achieve both high productivity and high manufacturing precision by applying different conditions at different stages.
Solution Approach 2:
The patent applies parameter changes between the two nitridation processes: the first process uses parameters optimized for maximum nitrogen incorporation (high efficiency), while the second process uses different parameters (such as modified plasma conditions, temperature, or gas composition) that enable selective nitrogen removal from isolation regions. This parameter transformation allows the process to achieve both high productivity and high selectivity.
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 achieves a high selectivity of nitrogen incorporation in silicon or polysilicon materials, minimizing nitrogen in shallow trench isolation regions and improving the reliability of tunnel oxides, thus enhancing the performance and scalability of NAND flash memory devices.
Implementation Method 1
A remote plasma system is used to generate and deliver plasma radicals at an angle to a processing chamber
Data Source
AI summary
Embodiments of the disclosure provide an improved apparatus and methods for nitridation of stacks of materials. In one embodiment, a method for processing a substrate in a processing region of a process chamber is provided. The method includes generating and flowing plasma species from a remote plasma source to a delivery member having a longitudinal passageway, flowing plasma species from the longitudinal passageway to an inlet port formed in a sidewall of the process chamber, wherein the plasma species are flowed at an angle into the inlet port to promote collision of ions or reaction of ions with electrons or charged particles in the plasma species such that ions are substantially eliminated from the plasma species before entering the processing region of the process chamber, and selectively incorporating atomic radicals from the plasma species in silicon or polysilicon regions of the substrate.