Inductively Coupled Impedance Matching Network for Lower Thermal Load
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Solution Overview
Problem
Impedance matching networks in plasma processes face significant thermal loads due to energy dissipation, leading to increased component requirements and costs, and limitations on the use of certain components like capacitors.
Innovation Solution
An impedance matching network with two transmission lines coupled via an inductive coupling element, allowing components to be decoupled electrically and cooled through a common reference potential, enabling the use of solid-state switches for fast impedance adaptation and reducing thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an impedance matching network is provided adjacent to the chamber feed unit, then the efficiency of power transfer into the plasma is optimized, but significant thermal load is generated due to energy dissipation
Solution Approach 1:
The impedance matching network is divided into multiple sections with different electrical potentials. The high-power components (circulators, isolators) are separated from the sensitive tuning components (capacitors, switches) by isolating sections. This segmentation allows thermal management by placing heat-generating components in well-cooled high-power sections while keeping sensitive components in lower-thermal-load sections.
Solution Approach 2:
Electrical isolating sections act as intermediaries between high-power sections and sensitive tuning sections. These isolating sections provide electrical isolation while maintaining RF signal transmission, allowing the two sections to operate at different thermal conditions without direct thermal or electrical coupling.
2Reliability
If components are placed in high thermal load areas, then the impedance matching function is maintained, but the requirements on component thermostability increase, leading to increased spatial requirements and manufacturing costs
Solution Approach 1:
The network is segmented into thermal zones, allowing components with different thermostability requirements to be placed in appropriate zones. This reduces the overall complexity by not requiring all components to meet the highest thermal specifications.
Solution Approach 2:
Different sections of the network have different thermal characteristics tailored to the specific requirements of the components placed in each section. High-power sections are designed for thermal management, while sensitive sections are designed for component protection, optimizing local conditions for each component type.
3Volume of stationary object
If certain types of capacitors are used in high thermal load areas, then the impedance matching network can be compact, but the thermal load may prevent the use of certain components
Solution Approach 1:
The network is divided into sections that can accommodate different capacitor types based on their thermal tolerance. This allows the use of compact high-power capacitors in well-cooled sections while using more sensitive but functionally appropriate capacitors in lower-thermal-load sections.
Solution Approach 2:
The thermal parameters of different sections are optimized to match the requirements of specific capacitor types. By controlling local thermal conditions through the segmented architecture, a wider variety of capacitor types can be used throughout the network.
4Speed
If solid-state switches are used for impedance adaptation, then the tuning speed is enhanced, but the components are more susceptible to thermal load
Solution Approach 1:
Electrical isolating sections serve as intermediaries that protect solid-state switches from high thermal loads in high-power sections. The isolating sections maintain RF signal transmission while electrically and thermally separating the heat-sensitive switches from heat-generating components.
Solution Approach 2:
The network is segmented to place solid-state switches in protected sections with lower thermal loads, while high-power components are isolated in separate well-cooled sections. This allows solid-state switches to operate at their full speed potential without being limited by thermal constraints.
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 design reduces thermal load on components, allows for the use of more versatile components, enhances tuning speed, and lowers maintenance costs while maintaining efficient energy transfer to the plasma.
Implementation Method 1
the coupling element provides an inductive coupling between the first transmission line and the second transmission line
Implementation Method 2
an RF power generator is connected to a chamber feed unit that transfers the power of the RF signal generated by the RF power generator into a plasma chamber
Implementation Method 3
Due to energy dissipation caused e.g. by ohmic resistances and dielectric heating, there may be significant thermal load on at least portions of the impedance matching network
Implementation Method 4
Due to energy dissipation caused e.g. by ohmic resistances and dielectric heating, there may be significant thermal load on at least portions of the impedance matching network
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
An impedance matching network (20) for plasma processes is described. The impedance matching network (20) comprises an input port (28) being connectable to a radio frequency, RF, generator module. The impedance matching network (20) further comprises an output port (30) being connectable to a load. The impedance matching network (20) further comprises a transmission circuit (32), wherein the transmission circuit (32) connects the output port (30) to the input port (28). The transmission circuit (32) comprises a first transmission line (34) and a second transmission line (36), wherein the first transmission line (34) is electrically connected to the input port (28), and wherein the second transmission line (36) is electrically connected to the output port (30). The impedance matching network (20) further comprises a first impedance matching module (48), wherein the first impedance matching module (48) is configured to connect at least one reactance to the transmission circuit (32). The impedance matching network (20) further comprises a coupling element (38), wherein the first transmission line (34) and the second transmission line (36) are coupled to each other by the coupling element (38), and wherein the coupling element (38) provides an inductive coupling between the first transmission line (34) and the second transmission line (36). Further, an impedance matching control system, and a method of impedance matching are described.