RF Match Network Sensor Calibration for Complex Impedance Tuning
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Solution Overview
Problem
Existing match networks for RF power delivery in plasma processing face challenges in accurately calibrating sensors to match variable impedances, particularly due to errors between sensors when used in combination, especially when operating with complex wave impedances, leading to inefficiencies in power transfer.
Innovation Solution
A method that involves self-calibration of individual sensors and mutual calibration of sensors relative to each other, using a mutual load to account for errors between sensors, allowing for accurate operation over a wide range of impedance values by determining and applying displacement matrices to modify calibration matrices, thereby improving impedance matching precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If single or dual sensor calibration is performed assuming real impedance R0, then calibration can be completed using standard methods, but measurement precision deteriorates when operating with complex wave impedances
Solution Approach 1:
The patent changes the impedance parameter from real R0 to complex wave impedance Z0 in the calibration process. This allows the calibration to account for both magnitude and phase of the impedance, significantly improving measurement precision when operating with complex wave impedances while maintaining a manageable calibration process through systematic measurement steps.
2Ease of manufacture
If sensors are calibrated in isolation using self-calibration methods, then calibration cost is reduced, but errors between sensors when used in combination increase
Solution Approach 1:
The patent introduces a mutual load as an intermediary element that couples the sensors together during calibration. This mutual load serves as a mediator that allows the sensors to be calibrated in relation to each other rather than in complete isolation, enabling the capture of interaction errors between sensors while still using affordable sensor components.
Solution Approach 2:
The patent replaces the traditional isolated calibration approach with a mutual calibration approach that uses electrical measurements through a mutual load. This substitution allows for capturing sensor interaction effects that would be missed in isolated calibration, improving sensor compatibility without requiring expensive reference sensors.
3Loss of energy
If match network is designed for efficient power transfer, then power delivery efficiency is improved, but adaptability to varying impedance conditions deteriorates
Solution Approach 1:
The patent implements dynamic calibration matrices that can be applied across varying impedance conditions. The calibration process creates transformation matrices that adapt to different operating points, allowing the match network to maintain efficient power transfer across a wide range of impedance conditions rather than being optimized for a single fixed impedance.
Data Source
AI summary
This disclosure describes systems, methods, and apparatus for calibrating sensors used by a match network during tuning of power delivery to a plasma processing chamber. The calibration can include self-calibration of two sensors in isolation relative to a self-load, and Relative or Absolute mutual calibration of both sensors used together across a mutual load. The mutual calibration can determine errors between the two sensors after they are each calibrated in isolation, and this additional calibration provides previously unrealized tuning accuracy.