Boron Nitride Film Deposition With Hydrogen-Free Plasma Purification
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Solution Overview
Problem
Existing boron nitride (BN) film forming methods, such as those described in Patent Documents 1 to 3, fail to achieve sufficient film-formation properties, adhesion, and film quality, particularly for hexagonal BN (h-BN) films.
Innovation Solution
A method involving multiple sequences, each comprising the supply of a source gas containing a borazine-based compound and plasma to a substrate, followed by the supply of plasma without the source gas, with at least a portion of the sequences including the supply of hydrogen-free plasma for modification after the plasma supply without the source gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional BN film forming methods are used, then film formation is achieved, but film-formation properties, adhesion, and film quality are insufficient
Solution Approach 1:
The film formation process is divided into multiple sequences, each consisting of three distinct steps: (1) supplying source gas containing borazine-based compound, (2) supplying plasma without source gas, and (3) supplying hydrogen-free plasma for modification. This segmentation allows each step to optimize specific film properties independently, resolving the contradiction between film quality and adhesion by addressing them in sequential phases rather than simultaneously
Solution Approach 2:
The invention changes multiple process parameters throughout the sequences: gas composition (from hydrogen-containing to hydrogen-free), plasma power, pressure, and temperature. By dynamically adjusting these parameters across the three steps, the method achieves both improved film-formation properties and adhesion, transforming the trade-off into a multi-stage optimization process
2Productivity
If plasma is supplied continuously with source gas, then film deposition is efficient, but hydrogen content in the film increases reducing oxidation resistance
Solution Approach 1:
The invention performs preliminary actions in a specific sequence: first depositing film material with hydrogen-containing plasma, then removing hydrogen through hydrogen-free plasma treatment in the third step. This preliminary deposition followed by hydrogen removal resolves the contradiction by ensuring high deposition efficiency first, then eliminating the harmful hydrogen content in a controlled manner
Solution Approach 2:
The invention converts the harmful effect of hydrogen incorporation during deposition into a beneficial process by intentionally allowing hydrogen incorporation in step 1, then using step 3's hydrogen-free plasma to remove the hydrogen. This transforms the harmful hydrogen content issue into a controlled two-stage process where hydrogen is first introduced for efficient deposition, then removed to improve oxidation resistance
3Manufacturing precision
If multiple process steps are added to improve film quality, then adhesion and oxidation resistance improve, but process complexity increases
Solution Approach 1:
The plasma source serves multiple functions across the three steps: it deposits film material in step 1, continues deposition without source gas in step 2, and performs hydrogen removal modification in step 3. This multi-functionality of the same equipment reduces device complexity while achieving improved film-formation properties through process variation rather than equipment multiplication
Solution Approach 2:
The invention uses periodic action by repeating the three-step sequence multiple times to build up the film layer by layer. Each cycle follows the same periodic pattern of (source gas+plasma) → (plasma only) → (hydrogen-free plasma), which simplifies control compared to continuously varying parameters, while still achieving high film quality through repeated cyclic processing
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 h-BN films with improved adhesion to the substrate, surface flatness, and overall film quality, as well as reduced hydrogen content, leading to enhanced oxidation resistance and a more stoichiometric B/N ratio.
Implementation Method 1
supplying plasma of a hydrogen-containing gas to the substrate
Implementation Method 2
supplying plasma of a hydrogen-free gas to the substrate after the supplying the plasma without the source gas
Implementation Method 3
supplying a source gas containing a borazine-based compound and plasma to a substrate
Implementation Method 4
supplying a source gas containing a borazine-based compound and plasma to a substrate disposed inside a chamber
Data Source
AI summary
A method of forming a boron nitride film includes performing plurality of sequences, each of the plurality of sequences including supplying a source gas containing a borazine-based compound and plasma to a substrate disposed inside a chamber and subsequently supplying the plasma to the substrate without the source gas, wherein each of at least a portion of the plurality of sequences includes supplying plasma of a hydrogen-free gas to the substrate after the supplying the plasma without the source gas. The supplying the source gas containing the borazine-based compound and the plasma includes supplying the source gas and plasma of a hydrogen-containing gas to the substrate, and the supplying the plasma without the source gas includes supplying the plasma of the hydrogen-containing gas without the source gas.