Silicon Nitride Deposition Using Halogen Plasma and TSA
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Solution Overview
Problem
Existing deposition methods for silicon nitride films face challenges in achieving high-quality films at low temperatures and high cycle rates, with current silicon raw materials like dichlorosilane, diiodosilane, and trisilylamine having limitations in film thickness uniformity, handling by-products, and vapor pressure issues.
Innovation Solution
A deposition method involving sequential exposure of a substrate to nitrogen and hydrogen plasmas, followed by a halogen plasma, and then trisilylamine (TSA) to promote dehydrogenation over silylation reactions, enhancing the cycle rate and film quality at low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional silicon raw materials (dichlorosilane, diiodosilane) are used for deposition, then film deposition can be achieved, but film thickness uniformity deteriorates and handling by-products increase
Solution Approach 1:
The invention changes the chemical parameters of the silicon raw material from conventional dichlorosilane or diiodosilane to trisilylamine (TSA). This parameter change in the raw material composition eliminates the by-product handling issues associated with chlorine and iodine compounds while improving film thickness uniformity through TSA's molecular structure and reaction characteristics.
2Temperature
If low temperature deposition is pursued, then energy consumption is reduced, but film quality deteriorates
Solution Approach 1:
The invention changes multiple parameters simultaneously: using TSA as the silicon source, introducing chlorine plasma treatment before deposition, and optimizing the plasma activation conditions. These combined parameter changes enable high-quality film formation at low temperatures by enhancing surface reactivity and improving adsorption efficiency without requiring high thermal energy.
Solution Approach 2:
The invention introduces chlorine plasma as an intermediary step between substrate preparation and TSA deposition. The chlorine plasma treatment modifies the substrate surface to enhance TSA adsorption and reaction efficiency, enabling quality film formation at low temperatures by mediating the interaction between the silicon source and substrate.
3Productivity
If high cycle rate is achieved, then productivity is improved, but film quality deteriorates
Solution Approach 1:
The invention optimizes the deposition cycle parameters by using TSA with its unique molecular structure that enables rapid adsorption and reaction. The shortened process steps and enhanced reaction kinetics of TSA allow high cycle rates to be achieved without compromising film quality, unlike conventional silicon sources that require longer processing times.
4Temperature
If trisilylamine (TSA) is used as silicon source, then vapor pressure is improved, but dehydrogenation reaction becomes dominant causing film quality issues
Solution Approach 1:
The invention introduces chlorine plasma as an intermediary that reacts with the substrate surface to create highly reactive sites. This chlorine treatment mediates the subsequent TSA adsorption and decomposition, directing the reaction pathway toward silylation rather than dehydrogenation, thereby maintaining film quality despite TSA's inherent dehydrogenation tendency.
Solution Approach 2:
The invention performs preliminary chlorine plasma treatment of the substrate before TSA deposition. This preliminary action modifies the substrate surface to be more receptive to TSA adsorption and to promote the desired silylation reaction, preventing the problematic dehydrogenation pathway that would otherwise dominate with TSA as the silicon source.
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 method allows for the deposition of high-quality silicon nitride films at low temperatures with improved cycle rates by optimizing the adsorption and reaction processes, specifically by decreasing the activation energy for TSA adsorption on chlorinated surfaces.
Implementation Method 1
exposing the substrate to a plasma formed from a nitriding gas containing nitrogen (N) and hydrogen (H)
Implementation Method 2
exposing the substrate to a plasma formed from hydrogen (H2) gas
Implementation Method 3
exposing the substrate to a plasma formed from a process gas containing a halogen
Data Source
AI summary
A deposition method of depositing a silicon nitride film on a surface of a substrate includes: (a) exposing the substrate to a plasma formed from a nitriding gas containing nitrogen (N) and hydrogen (H); (b) exposing the substrate to a plasma formed from hydrogen (H2) gas; (c) exposing the substrate to a plasma formed from a process gas containing a halogen; (d) supplying trisilylamine (TSA) to the substrate; and (e) repeating (a) to (d) in this order.