Elongated Capacitive Plasma Source With Sliding Ground
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Solution Overview
Problem
Existing substrate processing systems face challenges in controlling plasma ignition at medium pressures and accommodating thermal expansion, leading to inefficiencies and increased system footprint due to the need for precise gap control between RF hot electrodes and grounded surfaces.
Innovation Solution
A modular capacitively coupled plasma source assembly with an elongate housing, RF hot electrode, dielectric spacers, sliding ground connections, and coaxial RF feed lines, which maintains a gas tight seal and allows for thermal expansion while preventing stray plasma ignition through careful design of dielectric layers and gas flow paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gap control between RF hot electrode and grounded surface is tightened to avoid spurious plasma ignition, then plasma control reliability improves, but mechanical design complexity and difficulty of accommodating thermal expansion increase
Solution Approach 1:
The plasma source is divided into modular segments with standardized gap control features. The electrode assembly is segmented into replaceable modules that maintain precise gaps through standardized mechanical interfaces, reducing overall design complexity while ensuring reliable plasma ignition control.
Solution Approach 2:
The design incorporates thermal expansion compensation by allowing gap parameters to change dynamically with temperature. Flexible seals and adjustable mounting mechanisms enable the gap to accommodate thermal expansion while maintaining sufficient precision to prevent spurious plasma ignition.
2Area of stationary object
If modular plasma source design is implemented to reduce system footprint, then space efficiency improves, but access for operation and maintenance may be limited
Solution Approach 1:
The plasma source is designed as a modular assembly with clearly defined segments that can be independently accessed and maintained. The electrode, dielectric, and seal components are arranged in a standardized configuration that allows front-side access for routine operations while maintaining a compact overall footprint.
Solution Approach 2:
Front-accessible interface components serve as intermediaries between the operator and internal plasma source components. Quick-connect interfaces and removable covers enable maintenance personnel to access internal components from the front without requiring access to the rear or sides of the system.
3Stability of the object's composition
If precise gap control mechanisms are added to accommodate thermal expansion, then plasma stability improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The design accepts controlled parameter changes in the gap dimension to accommodate thermal expansion. Rather than rigidly maintaining a fixed gap, the system allows the gap to expand with temperature while maintaining sufficient precision through flexible seal design and standardized mounting features that are manufacturable with conventional tolerances.
Solution Approach 2:
The plasma source structure utilizes self-adjusting features where thermal expansion naturally maintains optimal gaps without active control. The flexible seals and elastic mounting elements automatically compensate for thermal effects, eliminating the need for complex active control mechanisms and simplifying manufacturing.
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 enhances processing efficiency and throughput by minimizing spurious plasma formation, reducing system footprint, and ensuring uniform plasma treatment across substrates, thereby improving the cost of ownership and operational efficiency of substrate processing systems.
Implementation Method 1
modular capacitively coupled plasma sources for use with batch reactors
Implementation Method 2
control of the gaps between RF hot electrodes and grounded surfaces can be important to avoid ignition of stray plasmas
Implementation Method 3
The end dielectric is in contact with each of the first end and the second end of the RF hot electrode and between the RF hot electrode and the side wall
Implementation Method 4
The seal foil is positioned at each sliding ground connection opposite the end dielectric. The seal foil forms an electrical connection between the front face of the elongate housing and the sliding ground connection
Implementation Method 5
The need to accommodate thermal expansion will require new designs to control gaps, and avoid spurious plasmas
Data Source
AI summary
A modular plasma source assembly for use with a processing chamber is described. The assembly includes an RF hot electrode with an end dielectric and a sliding ground connection positioned adjacent the sides of the electrode. A seal foil connects the sliding ground connection to the housing to provide a grounded sliding ground connection separated from the hot electrode by the end dielectric. A coaxial feed line passes through a conduit into the RF hot electrode isolated from the processing environment so that the coaxial RF feed line is at atmospheric pressure while the plasma processing region is at reduced pressure.