Cooled ICP Shield Structure for Dielectric Wall Heat Control
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Solution Overview
Problem
Plasma sources in high-power applications face overheating issues due to energy transmission through dielectric materials, leading to material degradation and potential failure, particularly in inductively coupled plasma sources where the area near the inductive coil experiences high heat, necessitating both shielding and cooling solutions that do not compromise RF power efficiency or increase arcing risks.
Innovation Solution
A shielding device comprising thermal pads surrounding the dielectric wall, connected to a heat sink via cooling channels, and elastic retaining members to maintain contact pressure and accommodate thermal expansion, while also providing electrical conductivity and reducing capacitive coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a traditional Faraday cage shielding structure is used, then electrical shielding is improved, but device complexity and cost increase
Solution Approach 1:
The inductive coil assembly serves dual functions: generating RF power for plasma generation and providing electrical shielding through its conductive structure. The coil acts as both the power source and the Faraday cage, eliminating the need for separate shielding structures and reducing overall device complexity.
Solution Approach 2:
The patent combines the shielding function with the inductive coil assembly by positioning the coil between the RF power source and the dielectric wall. This merging of functions allows the same component to provide both RF power delivery and electromagnetic shielding, simplifying the overall system architecture.
2Temperature
If cooling structures are added to manage heat, then thermal management is improved, but device complexity increases
Solution Approach 1:
The inductive coil assembly performs multiple functions simultaneously: RF power generation, electrical shielding, and heat management. The conductive coil structure conducts heat away from the dielectric wall while maintaining its primary functions, eliminating the need for separate cooling structures and reducing device complexity.
Solution Approach 2:
The inductive coil assembly serves itself by using its own conductive structure to manage heat generation. The coil's inherent electrical conductivity allows it to act as a heat sink, conducting thermal energy away from critical areas without requiring external cooling systems.
3Use of energy by moving object
If the inductive coil is positioned closer to the dielectric wall, then RF power efficiency is improved, but thermal stress and arcing risk increase
Solution Approach 1:
The inductive coil assembly acts as an intermediary between the RF power source and the dielectric wall. It delivers RF power efficiently while simultaneously providing electrical shielding and heat management, mediating the interaction to prevent direct arcing between the power source and dielectric surface.
Solution Approach 2:
The patent converts the potentially harmful thermal energy generated near the dielectric wall into a beneficial effect by using the inductive coil's conductive structure to conduct heat away. The heat that could cause damage is instead utilized for thermal management, improving reliability while maintaining RF efficiency.
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 effectively manages heat transfer from the dielectric wall, mitigates thermal stresses, and maintains RF efficiency by accommodating thermal expansion, reducing the risk of material failure and arcing, while being cost-effective compared to traditional Faraday cage modifications.
Implementation Method 1
a plurality of thermal pads coupled to top annular portion and/or bottom annular portion with one or more retaining members
Implementation Method 2
connected to a heat sink via cooling channels
Implementation Method 3
elastic retaining members to maintain contact pressure and accommodate thermal expansion
Implementation Method 4
reducing capacitive coupling
Data Source
AI summary
Provided is a plasma processing apparatus or system including a plasma chamber and an inductively coupled plasma source. A shielding device is disposed between the plasma chamber the inductively coupled plasma source. The shielding device includes a top annular portion, a bottom annular portion, and a plurality of thermal pads coupled to top annular portion and/or bottom annular portion with one or more retaining members. The one or more retaining members provide a compressive force to secure the one or more thermal pads against the outer surface of the dielectric wall. The plurality of thermal pads are configured to modulate a heat flux from the dielectric wall into the respective thermal pad. Methods of processing workpieces are also disclosed.