Silicon Nitride ALD Using N2/H2 Plasma for Low Wet Etch
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Solution Overview
Problem
Existing methods for depositing silicon nitride films using atomic layer deposition face challenges in achieving low wet etch rates while maintaining high growth rates and conformality, due to the undesired side effects of using ammonia plasma, such as particle generation and metal corrosion.
Innovation Solution
The method involves an NH3-free process using a combination of N2 and H2 plasma steps in atomic layer deposition, where an H2 plasma step is inserted after the initial N2 plasma step, optimizing the flow, pressure, and power to achieve high throughput and low wet etch rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ammonia plasma is used in atomic layer deposition, then high growth rates are achieved, but particle generation and metal corrosion occur
Solution Approach 1:
The patent extracts ammonia from the plasma process entirely, replacing it with a two-step plasma approach using nitrogen plasma followed by hydrogen plasma. This removes the source of particle generation and metal corrosion while maintaining the nitrogen incorporation needed for silicon nitride film formation, thereby achieving high growth rates without the harmful side effects of ammonia plasma
Solution Approach 2:
The patent introduces hydrogen plasma as an intermediary step between silicon precursor dosing and nitrogen plasma exposure. This hydrogen plasma step passivates the surface and prevents unwanted reactions, enabling the use of nitrogen plasma for nitrogen incorporation without the need for ammonia, thus eliminating particle generation and metal corrosion while maintaining film quality and growth rate
2Productivity
If ammonia plasma is used in atomic layer deposition, then high growth rates are achieved, but metal corrosion occurs
Solution Approach 1:
The patent removes ammonia from the deposition process entirely, replacing it with nitrogen plasma followed by hydrogen plasma steps. This extraction eliminates the corrosive action of ammonia on metal chamber components while maintaining efficient nitrogen incorporation into the silicon nitride film, achieving high growth rates without metal corrosion
Solution Approach 2:
The patent uses a short-duration hydrogen plasma step as a protective measure between silicon dosing and nitrogen plasma exposure. This brief hydrogen plasma treatment passivates the surface and protects metal components from corrosion during the subsequent nitrogen plasma step, enabling high growth rates without compromising chamber integrity
3Quantity of substance
If conventional atomic layer deposition is used, then silicon nitride films are deposited, but wet etch rates are high
Solution Approach 1:
The patent changes the chemical parameters of the plasma process by eliminating ammonia and using nitrogen plasma followed by hydrogen plasma instead. This parameter change alters the film composition and bonding structure, resulting in silicon nitride films with lower wet etch rates while maintaining conformal deposition and high growth rates through optimized plasma power and duration
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 results in a conformal silicon nitride film with high growth rates, low wet etch rates, reduced particle generation, and no upstream metal corrosion, thereby improving the commercial attractiveness and cost-effectiveness of the film deposition process.
Implementation Method 1
providing an N2 plasma conversion
Implementation Method 2
depositing a silicon nitride layer on a stack by providing a plurality of cycles, wherein each of the cycles of the plurality of cycles, comprises dosing the stack with a silicon containing precursor
Implementation Method 3
providing an H2 plasma conversion
Data Source
AI summary
A method for depositing a silicon nitride layer on a stack is provided. The method comprises providing an atomic layer deposition, comprising a plurality of cycles, wherein each cycle comprises dosing the stack with a silicon containing precursor by providing a silicon containing precursor gas, providing an N2 plasma conversion, and providing an H2 plasma conversion.