Phase Detection Circuit for Plasma Impedance Matching
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Solution Overview
Problem
Current impedance matching networks in plasma applications face challenges in quickly and reliably adjusting to varying impedance conditions, requiring faster and more precise measurement of voltage and current amplitudes and their phase difference to ensure optimal power transfer in semiconductor processing.
Innovation Solution
A phase detection circuit and impedance matching network incorporating electronically variable capacitors (EVCs) that utilize a high-pass and low-pass filter to create a 90-degree phase offset, allowing for real-time determination of phase angle differences and subsequent adjustment of impedance to match changing plasma conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional impedance matching networks are used in plasma applications, then the system can operate with basic impedance matching capability, but the speed and reliability of adjusting to varying impedance conditions is insufficient
Solution Approach 1:
The patent implements dynamically adjustable impedance matching by replacing fixed capacitors with electronically variable capacitors (EVCs) that can be controlled in real-time. The system continuously monitors voltage and current signals and adjusts capacitor values dynamically to maintain optimal impedance matching as plasma conditions change, thereby improving both reliability and response speed.
Solution Approach 2:
The patent employs a feedback control system that measures voltage amplitude, current amplitude, and phase difference between these signals. This feedback information is used to calculate impedance parameters and adjust the EVC settings accordingly, enabling the system to automatically adapt to varying plasma impedance conditions with high reliability and speed.
2Speed
If faster measurement of voltage and current amplitudes and phase difference is implemented, then the speed of impedance adjustment improves, but the device complexity increases
Solution Approach 1:
The patent introduces a phase detection circuit as an intermediary component that simplifies the measurement process. This circuit uses high-pass and low-pass filters to extract in-phase and quadrature components of the signals, making it easier and faster to determine phase difference without requiring complex direct measurement techniques.
Solution Approach 2:
The patent replaces complex mechanical or direct electrical measurement methods with an electronic signal processing approach. By using filter-based phase detection and digital signal processing algorithms, the system achieves fast measurement of phase difference and amplitude with reduced hardware complexity compared to traditional measurement techniques.
3Manufacturing precision
If more precise determination of phase angle difference is achieved, then the manufacturing precision of impedance matching improves, but the device complexity increases
Solution Approach 1:
The patent uses high-pass and low-pass filters as intermediary elements to separate signal components. This filtering approach provides precise phase angle determination by cleanly separating in-phase and quadrature components, achieving high measurement precision without requiring overly complex measurement instrumentation.
Solution Approach 2:
The phase detection circuit creates simplified copies or representations of the original signals through filtering. By generating filtered versions of voltage and current signals that represent specific phase components, the system achieves precise phase measurement using simpler circuitry than would be needed for direct high-precision measurement.
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 enables more efficient and reliable impedance matching, enhancing the precision and speed of semiconductor processing by accurately adjusting to dynamic impedance changes, thereby improving power transfer and process repeatability.
Implementation Method 1
a high-pass filter and a low-pass filter each configured to filter one of (i) the current signal from the current signal input or (ii) the voltage signal from the voltage signal input, wherein the high-pass filter and the low-pass filter collectively cause a substantially 90 degree offset between a phase angle of the current signal and a phase angle of the voltage signal
Data Source
AI summary
In one embodiment, a phase detection circuit includes a current signal input to receive a current signal indicative of a current amplitude of an RF signal and a voltage signal input to receive a voltage signal indicative of a voltage amplitude of the RF signal. A high-pass filter and a low-pass filter are each configured to filter one of (i) the current signal from the current signal input or (ii) the voltage signal from the voltage signal input, wherein the high-pass filter and the low-pass filter collectively cause a substantially 90 degree offset between a phase angle of the current signal and a phase angle of the voltage signal. A phase difference circuit receives the filtered current signal and the filtered voltage signal to determine a phase angle difference between the current signal and the voltage signal.