Faraday Shielding Plate Heating Circuit for Plasma Etching
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Solution Overview
Problem
Existing plasma etching systems face issues with low heating efficiency and structural complexity due to capacitive coupling, leading to local sputtering and deposition on dielectric windows, which causes defects and requires manual cleaning.
Innovation Solution
A Faraday shielding apparatus with a conductive ring and petal-shaped members is used for direct heating of the dielectric window, incorporating a heating circuit, filter circuit, and feedback control to maintain optimal temperature, reducing deposition and simplifying the equipment structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a fan is used to blow heated air to the dielectric window, then the dielectric window can be heated, but the heating efficiency is low and heat is scattered
Solution Approach 1:
The patent replaces the mechanical fan-based heating system with an electromagnetic induction heating system. The induction heating coil generates an electromagnetic field that directly induces eddy currents in the dielectric window, heating it efficiently without mechanical air movement. This eliminates heat scattering and significantly improves heating efficiency.
Solution Approach 2:
The patent utilizes electromagnetic field phase transitions and energy conversion. The electromagnetic field from the induction coil transforms into thermal energy through eddy current heating of the dielectric window, providing direct and efficient heating without the intermediate step of heating air and using convection.
2Loss of energy
If external shielding cover is added to prevent heat dispersion, then heat loss is reduced, but the structure becomes complex and occupies additional space
Solution Approach 1:
The patent replaces the mechanical external shielding cover with an electromagnetic field-based solution. The induction heating coil is positioned and oriented to create a focused electromagnetic field that naturally confines heat to the dielectric window area, eliminating the need for physical shielding structures.
Solution Approach 2:
The patent uses the electromagnetic field itself as a flexible 'shield' that can be precisely controlled and directed. The electromagnetic field acts as an invisible barrier that confines energy without requiring physical barriers, maintaining simplicity while preventing heat loss.
3Temperature
If heating is applied to coils and electrical components, then they can be maintained at appropriate temperatures, but high temperature causes easy damages to electrical components
Solution Approach 1:
The patent extracts the heating function from the electrical components (coils and matchers) and applies it specifically to the dielectric window. The induction heating coil is designed to heat only the dielectric window through controlled electromagnetic field interaction, while electrical components remain at safe operating temperatures, improving their reliability.
Solution Approach 2:
The patent implements localized heating where the induction heating coil is positioned and oriented to create a focused electromagnetic field that heats only the dielectric window. Electrical components are positioned outside this focused field zone, experiencing minimal thermal exposure and maintaining their durability.
4Loss of substance
If manual cleaning is performed to remove deposition from dielectric window, then deposition is removed, but the process requires disassembly and increases maintenance time
Solution Approach 1:
The patent applies preliminary action by continuously or periodically heating the dielectric window during or between etching cycles. This prevents deposition from accumulating to problematic levels, eliminating the need for frequent disassembly and manual cleaning operations.
Solution Approach 2:
The patent implements continuous heating action to prevent deposition accumulation. By maintaining the dielectric window at an elevated temperature during operation, the system continuously reduces deposition, eliminating the need for periodic maintenance shutdowns and manual cleaning.
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 solution achieves high heating efficiency with reduced heat loss and simplified equipment structure, effectively minimizing deposition on the dielectric window and preventing radio-frequency interference during the etching process.
Implementation Method 1
the Faraday shielding plate is heated by electricity
Implementation Method 2
the Faraday shielding plate in direct contact with the dielectric window to increase the temperature
Implementation Method 3
Faraday shielding apparatus which can be used for heating and plasma etching system
Data Source
AI summary
A Faraday shielding apparatus includes a Faraday shielding plate and a heating circuit; the Faraday shielding plate includes a conductive ring and a plurality of conductive petal-shaped members radially symmetrically connected to the outer periphery of the conductive ring; when the heating circuit is used in the etching process, the Faraday shielding plate is heated by electricity. During the etching process, the heating circuit is conductively connected to the Faraday shielding plate, increasing the temperature of the Faraday shielding plate when it is energized, heating a medium window and reducing the amount of product deposits. During the cleaning process, the heating circuit and the Faraday shield are turned off, and the Faraday shielding plate is connected to a shielding power supply to clean the dielectric window. The output terminal of the heating power supply is filtered by way of a filter circuit unit, then connected to the Faraday shielding plate.