RF Slip Ring Isolation Layout to Prevent PECVD Arcing
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Solution Overview
Problem
In plasma enhanced chemical vapor deposition (PECVD) reactors, the challenge is to prevent electrical breakdown and arcing between radio frequency (RF) and non-RF power lines due to voltage differences, especially in limited spaces where maintaining sufficient clearance is not feasible.
Innovation Solution
The implementation of a slip ring system that transfers both RF and non-RF power through multiple adjacent channels, using capacitors to block non-RF power and distribute RF power evenly among channels, minimizing voltage differences and reducing the risk of arcing, while allowing for closer proximity of power lines within the limited space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If clearance distance is increased between RF and non-RF signal lines to prevent electrical breakdown, then reliability is improved, but device complexity and space requirements worsen
Solution Approach 1:
The patent applies equipotentiality by ensuring that adjacent signal lines operating at different power types (RF and non-RF) are maintained at substantially the same voltage potential. This is achieved through careful circuit design where the voltage on RF signal lines and non-RF signal lines are balanced, eliminating voltage differences that would cause electrical breakdown. By making adjacent conductors equipotential, the patent allows them to be placed in close proximity without requiring large clearance distances, thus solving the contradiction between reliability and space requirements.
2Productivity
If multiple power types are transferred through adjacent channels in limited space, then productivity is improved, but the risk of electrical arcing worsens
Solution Approach 1:
The patent eliminates electrical arcing by maintaining equipotential conditions between adjacent signal lines carrying different power types. The circuit design ensures that RF and non-RF signal lines have substantially equal voltage potentials, removing the voltage difference that drives arcing. This allows multiple power types to be efficiently transferred through closely spaced adjacent channels without the harmful effect of electrical breakdown.
Solution Approach 2:
The patent uses capacitors as intermediary components in the signal lines to manage voltage potentials and block direct DC paths while allowing RF signals to pass. These capacitive elements act as mediators that help balance the voltage between adjacent channels, preventing arcing while maintaining power transfer efficiency. The capacitors are strategically placed to control the electrical characteristics of the signal paths.
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 solution effectively prevents electrical arcing and damage by ensuring minimal voltage differences between adjacent channels, allowing the system to operate safely and efficiently within the constrained space of a PECVD reactor.
Implementation Method 1
Each channel includes a capacitor in series with the combined power that blocks the non-RF power
Implementation Method 2
The slip ring transfers both RF and non-RF power through multiple adjacent channels, distributing RF power evenly among channels
Implementation Method 3
there may be a breakdown depending on levels of voltage potential in the signal lines and materials of insulators of the signal lines
Data Source
AI summary
An isolation system includes an input junction coupled to one or more RF power supplies via a match network for receiving radio frequency (RF) power. The isolation system further includes a plurality of channel paths connected to the input junction for distributing the RF power among the channel paths. The isolation system includes an output junction connected between each of the channel paths and to an electrode of a plasma chamber for receiving portions of the distributed RF power to output combined power and providing the combined RF power to the electrode. Each of the channel paths includes bottom and top capacitors for blocking a signal of the different type than that of the RF power. The isolation system avoids a risk of electrical arcing created by a voltage difference between an RF terminal and a non-RF terminal when the terminals are placed proximate to each other.