Chamber Cleaning Plasma Control Using Selectable Electrode Impedance
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Solution Overview
Problem
Existing methods for cleaning the inside of chambers in CVD or ALD processes are inefficient, particularly in areas outside the region between the RF electrode and the susceptor, leading to incomplete cleaning and reduced throughput.
Innovation Solution
A substrate treatment apparatus that includes a chamber, a susceptor with an electrode, a metal plate, and a selection device to connect impedance adjusters with different impedances to the electrode, allowing for the generation of plasma in a wide range of the chamber by adjusting the impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If direct plasma cleaning is carried out with oxygen plasma between RF electrode and susceptor, then cleaning efficiency in that region is improved, but cleaning efficiency in other areas (lower part of susceptor, inside exhaust duct) deteriorates
Solution Approach 1:
The patent divides the single RF electrode into multiple RF electrodes (first RF electrode facing the susceptor, second RF electrode facing the chamber wall). This segmentation allows independent plasma generation in different regions, enabling the first electrode to clean the susceptor area while the second electrode cleans the chamber wall and exhaust duct area simultaneously
Solution Approach 2:
The patent adds a spatial dimension to plasma generation by positioning RF electrodes at different locations (one between susceptor and chamber wall, another facing chamber wall). This multi-dimensional electrode arrangement enables plasma to be generated in previously inaccessible areas like the exhaust duct and lower susceptor regions, expanding cleaning coverage from a single plane to three-dimensional space
2Adaptability or versatility
If remote plasma cleaning is carried out with halogen, then cleaning coverage is improved, but damage to chamber parts occurs due to high film forming temperature (500°C or higher)
Solution Approach 1:
The patent replaces thermal-based remote plasma cleaning with electromagnetic-based direct plasma cleaning using RF electrodes. Instead of relying on high-temperature halogen plasma that causes thermal damage, the system uses localized electromagnetic field-driven plasma generation at lower temperatures, eliminating the harmful thermal effects while maintaining cleaning effectiveness
Solution Approach 2:
The patent changes the temperature parameter by using direct plasma generation at lower temperatures compared to remote plasma methods. By applying RF power directly to electrodes in specific regions, plasma is generated locally without requiring the high temperatures (500°C or higher) needed for remote plasma cleaning, thus preventing chamber part damage
3Object-affected harmful factors
If remote plasma cleaning is carried out with only oxygen, then chamber part damage is avoided, but active species are deactivated resulting in reduced cleaning efficiency
Solution Approach 1:
The patent applies different plasma conditions to different locations: oxygen plasma is used in regions requiring gentle cleaning (near susceptor), while other gases can be used in regions tolerant of higher reactivity (chamber wall, exhaust duct). This local differentiation allows active species to remain effective in appropriate zones without causing damage in sensitive areas
Solution Approach 2:
The patent introduces RF electrodes as intermediaries to generate plasma in situ. Instead of relying on remote plasma generation that deactivates active species before reaching the chamber, the RF electrodes create plasma locally at the target surfaces, ensuring active species are generated exactly where needed and maintain their cleaning effectiveness without being deactivated in transit
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 apparatus enables effective cleaning of the entire chamber by generating plasma in previously hard-to-reach areas, improving cleaning efficiency and reducing particle generation and throughput limitations.
Implementation Method 1
allowing for the generation of plasma in a wide range of the chamber by adjusting the impedance
Data Source
AI summary
Examples of a substrate treatment apparatus includes a chamber, a susceptor provided in the chamber and having an electrode therein, a metal plate facing the susceptor, a plurality of impedance adjusters having different impedances, and a selection device configured to connect one of the plurality of impedance adjusters to the electrode.