Multi-Feed Plasma Matching Circuit Compensation for Power and Phase
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Solution Overview
Problem
Impedance matching circuits in multi-feed plasma chambers cause unintended power loss and phase shifting, compromising accurate and uniform power delivery in semiconductor processing.
Innovation Solution
A system with variable network elements in matching circuits, coupled to a plasma chamber, stores parameter discrepancy data and uses a control circuit to adjust power and phase signals based on this data to minimize discrepancies, ensuring uniform power delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If impedance matching circuits are used to match between power source and plasma chamber, then power delivery is improved, but power loss and phase shifting occur
Solution Approach 1:
The system pre-characterizes each matching circuit at multiple match positions to determine compensation values for power loss and phase shift before actual plasma processing. This preliminary characterization allows the control system to apply pre-calculated compensation factors, eliminating the need for real-time iterative adjustments and reducing overall power loss while maintaining accurate power delivery.
Solution Approach 2:
The system implements a feedback mechanism where the actual power and phase at the plasma chamber are monitored, and compensation adjustments are applied based on the difference between desired and actual values. This closed-loop control ensures that power delivery accuracy is maintained while minimizing energy loss through optimal matching circuit operation.
2Reliability
If impedance matching circuits are used to match between power source and plasma chamber, then power delivery is improved, but phase shifting occurs
Solution Approach 1:
The system pre-measures and stores phase shift values for each matching circuit at every match position before processing. By having phase characterization data available in advance, the control system can apply precise phase compensation without introducing additional phase errors, thereby maintaining both power delivery accuracy and phase precision.
Solution Approach 2:
The system continuously monitors the actual phase at the plasma chamber and applies real-time phase compensation based on feedback from the actual versus desired phase comparison. This ensures that phase accuracy is maintained despite the inherent phase-shifting characteristics of the matching circuits.
3Adaptability or versatility
If multiple match positions are available in matching circuits, then adaptability is improved, but system complexity increases
Solution Approach 1:
The system performs comprehensive pre-characterization of all matching circuits at all possible match positions, storing power loss and phase shift data in lookup tables. This approach allows the system to handle complex multi-position matching scenarios through simple table lookups and arithmetic operations, effectively managing adaptability without proportionally increasing operational complexity.
Solution Approach 2:
The system uses a universal compensation algorithm that works across all matching circuits and all match positions. By implementing a single, multi-functional compensation mechanism that handles all positions uniformly, the system achieves high adaptability while avoiding the need for position-specific complex control logic.
Data Source
AI summary
In one embodiment, the present disclosure is directed to a system for providing energy to a plasma chamber having multiple power signal inputs. A power source transmits output signals to matching circuits. Each of the matching circuits provides different match positions. A memory stores, for each match position of each matching circuit, and for each output signal, parameter discrepancy data for a parameter, such as power or phase, of the output signal at an output of the matching circuit. For each of the matching circuits and its corresponding output signal, the control circuit causes the power source to alter the parameter based on the parameter discrepancy data, the alteration of the parameter preventing or decreasing the anticipated discrepancy between the desired value for the parameter and the actual value for the parameter.