Silicon Oxide Film Reforming with Low-Pressure Helium Microwave Plasma
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Solution Overview
Problem
Conventional post-deposition treatment methods for silicon oxide films, especially in high aspect ratio trenches, result in degraded film quality due to low ion irradiation on sidewalls, and high-temperature processes can damage materials with low melting points, limiting their application in semiconductor fabrication.
Innovation Solution
Exposing silicon oxide films to a reforming gas consisting of pure helium or a mixture of helium and hydrogen, irradiated with high-frequency microwave plasma at low pressures, to improve film quality and uniformity without oxygen, allowing for low-temperature processing and fast processing speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma treatment using oxygen gas is performed to reform silicon oxide film, then film quality is improved, but processing time is extended and material fusion occurs due to high temperature
Solution Approach 1:
The patent changes the plasma treatment parameters by using helium gas instead of oxygen gas, and controlling the pressure to 100 Pa or less. This parameter change enables effective film reformation at lower temperatures and shorter processing times, resolving the contradiction between film quality improvement and processing time extension.
Solution Approach 2:
The patent uses helium gas as an inert atmosphere for plasma treatment, replacing the conventional oxygen-based plasma. This inert environment prevents unwanted chemical reactions and material fusion while still achieving effective film reformation, thus improving film quality without extending processing time.
2Reliability
If high-temperature treatment process is used to deposit silicon oxide film by thermal oxidation method, then insulating property is improved, but material fusion and decomposition occur
Solution Approach 1:
The patent replaces the thermal oxidation method with a plasma-enhanced deposition method using helium plasma. This substitution allows film formation at lower temperatures, achieving high insulating properties without causing material fusion or decomposition of temperature-sensitive compounds.
Solution Approach 2:
The patent employs helium gas as an inert atmosphere during plasma treatment, preventing oxidative reactions and material degradation. This inert environment enables low-temperature processing that maintains material integrity while achieving the desired insulating properties.
3Shape
If PEALD is used to deposit silicon oxide film at low temperature, then conformality is improved, but film quality on sidewall of high aspect ratio recess is degraded due to low ion irradiation
Solution Approach 1:
The patent introduces helium plasma as an intermediary treatment step after PEALD deposition. This plasma treatment acts as a mediator that enhances ion irradiation to the sidewalls of high aspect ratio recesses, improving film quality and uniformity without compromising the conformality achieved by PEALD.
Solution Approach 2:
The patent changes the plasma treatment parameters by using helium gas at pressures of 100 Pa or less, which generates sufficient ion irradiation to reach and reform silicon oxide film on sidewalls of high aspect ratio structures. This parameter optimization resolves the film quality degradation issue while maintaining the low-temperature advantage of PEALD.
4Manufacturing precision
If post-deposition reforming process is performed to improve film quality, then film uniformity is improved, but processing temperature must be kept low to avoid material damage
Solution Approach 1:
The patent uses helium gas as an inert atmosphere for plasma-based post-deposition reforming, enabling effective film uniformity improvement at low temperatures. The inert helium environment prevents thermal damage to temperature-sensitive materials while the plasma activation provides sufficient energy for film reformation.
Solution Approach 2:
The patent replaces thermal annealing with plasma-enhanced reforming using helium plasma. This substitution eliminates the need for high temperatures while achieving the same or better film uniformity, as the plasma provides localized energy activation without bulk heating.
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
The method achieves significant film reformation with high in-plane uniformity and reduced wet etch rates, avoiding material fusion and oxidation, thus enabling the formation of high-quality silicon oxide films suitable for complex semiconductor structures and organic EL devices.
Implementation Method 1
irradiating the reforming gas with a reforming microwave plasma
Implementation Method 2
irradiated with high-frequency microwave plasma
Implementation Method 3
exposing a silicon oxide film to a reforming microwave plasma using a reforming gas
Implementation Method 4
perform a post-deposition reformation process on a silicon oxide film deposited at a low temperature
Data Source
AI summary
A method of post-deposition treatment for silicon oxide film includes: providing in a reaction space a substrate having a recess pattern on which a silicon oxide film is deposited; supplying a reforming gas for reforming the silicon oxide film to the reaction space in the absence of a film-forming precursor, said reforming gas being composed primarily of He and/or H2; and irradiating the reforming gas with microwaves in the reaction space having a pressure of 200 Pa or less to generate a direct microwave plasma to which the substrate is exposed, thereby reforming the silicon oxide film.