RF Synchronization Module for Plasma Chamber Power Control
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Solution Overview
Problem
In plasma chamber systems, existing RF measurement and control systems face challenges in accurately adjusting RF output parameters due to non-aligned sampling and processing frequencies, leading to overshooting or undershooting of target power levels, which affects the stability and efficiency of plasma processes.
Innovation Solution
The proposed RF system includes an RF sensor, analog-to-digital converter (ADC) modules, a processing module, and a synchronization module that measure and convert RF signal parameters, generating processed values aligned with transitions in the RF output, allowing for real-time adjustment of rail voltage and driver control setpoints to maintain accurate power control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RF measurement and control systems use independent sampling and processing frequencies, then system operation flexibility is maintained, but measurement and control become non-aligned causing overshooting or undershooting of target power levels
Solution Approach 1:
The patent merges the measurement and control operations by synchronizing them to a common RF pulsing clock signal. The ADC module and processing module both receive timing signals from the same clock source that generates RF pulses, ensuring that measurements are taken and control actions are executed at aligned time points within each RF cycle. This eliminates the phase misalignment between independent sampling and processing operations.
Solution Approach 2:
The patent implements a feedback mechanism where the processed measurement values are used to adjust RF output parameters in real-time. The system continuously measures RF power levels, processes these measurements through synchronization, and feeds the results back to control the RF generator, creating a closed-loop system that corrects power level deviations while maintaining temporal alignment between measurement and control actions.
2Speed
If RF output parameters are adjusted in real-time based on measurements, then control responsiveness is improved, but timing misalignment between measurement and control causes instability
Solution Approach 1:
The patent applies preliminary action by pre-synchronizing the measurement and control operations to the RF pulsing clock before any adjustments are made. The ADC sampling and processing timing are predetermined based on the RF cycle phase, ensuring that when real-time adjustments occur, they are temporally aligned with the RF output state. This prevents instability caused by reacting to measurements at inappropriate times within the RF cycle.
3Productivity
If multiple RF generators are used to service larger surface areas, then processing capacity is increased, but synchronization between generators becomes complex
Solution Approach 1:
The patent segments the RF generation system into multiple independent RF generators, each capable of servicing specific zones of the plasma chamber. By providing each generator with its own synchronized ADC and processing modules that all reference the same RF pulsing clock, the system achieves zoned control without requiring complex inter-generator synchronization. Each segment operates independently but in temporal harmony with the others.
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 ensures synchronized measurement and control, reducing overshoot and improving the repeatability and stability of RF output, thereby enhancing the efficiency and accuracy of plasma processes in systems like thin film manufacturing.
Implementation Method 1
An RF sensor measures a parameter of an RF output and generates an RF signal based on the parameter
Implementation Method 2
An analog to digital converter (ADC) module converts samples of the RF signal into digital values
Data Source
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AI summary
A radio frequency (RF) system, comprising: an analog to digital converter (ADC) module that converts samples of an RF signal into digital values, wherein the RF signal varies in accordance with an RF output, wherein the RF signal varies in accordance with a parameter of an RF output measured by a sensor; and further comprising at least one of: i) a processing module configured to generate a processed value based on the digital values; and a synchronization module configured to synchronize the outputting of the processed value with a transition in a second RF output; or ii) a synchronization module configured to synchronize the outputting of one of the digital values with a transition in a second RF output; and a processing module configured to generate a processed value based on the one of the digital values. Also, a corresponding radio frequency (RF) control method.