High-Voltage Power Supply Impedance Sensing for Electrostatic Chucks
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Solution Overview
Problem
Existing power supplies struggle to accurately measure the impedance or capacitance of loads, particularly electrostatic chucks, due to limitations in current measurement methods and flexibility in power supply configurations.
Innovation Solution
A power supply system that includes a current sensor, voltage sensor, and a sinewave oscillator generating alternating signals, coupled with a micro-controller to compute impedance or capacitance using digital data from these signals, enhancing accuracy and flexibility across different electrostatic chuck types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional current measurement methods are used in existing power supplies, then the power supply can operate with simpler measurement circuits, but the measurement precision of load impedance or capacitance is insufficient
Solution Approach 1:
The patent introduces a sinewave oscillator as an intermediary component that injects a test signal through the load to enable precise impedance measurement. The oscillator generates a sinusoidal voltage that flows through the load, and by measuring the resulting current and voltage, the system can calculate impedance with high precision without requiring complex direct measurement circuits
Solution Approach 2:
The patent replaces conventional direct current measurement methods with an alternating current-based measurement system. By using a sinewave oscillator to generate AC test signals and measuring the resulting AC current and voltage, the system achieves superior measurement precision for impedance and capacitance compared to traditional DC measurement approaches
2Adaptability or versatility
If the power supply uses fixed measurement configurations, then the device structure is simpler, but the adaptability to different electrostatic chuck types is reduced
Solution Approach 1:
The patent implements a universal measurement system that can adapt to different electrostatic chuck types (Coulomb and J-R types) through software configuration rather than hardware changes. The microcontroller can be programmed to perform different measurement algorithms depending on the chuck type, making the same physical device versatile across multiple applications without requiring separate measurement circuits for each chuck type
Solution Approach 2:
The patent introduces dynamic measurement capabilities where the system can switch between different measurement modes and algorithms based on the connected load type. The microcontroller dynamically adjusts the measurement approach - using capacitance measurement for Coulomb chucks and current measurement for J-R chucks - allowing the device to adapt its behavior to different conditions without physical reconfiguration
3Reliability
If simple measurement circuits are used in existing power supplies, then the device complexity is lower, but the reliability of impedance monitoring is insufficient
Solution Approach 1:
The patent implements feedback mechanisms where the measured impedance and capacitance values are continuously monitored and can trigger alerts or adjustments. The system uses the measured data to verify proper operation and detect faults, providing reliable monitoring that enhances system reliability through continuous feedback rather than simple one-time measurements
Solution Approach 2:
The patent performs preliminary measurements of load characteristics during system initialization or before operation begins. By measuring impedance and capacitance in advance, the system can verify proper connection and configuration before full operation, preventing unreliable operation and enabling early detection of potential issues
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
The system provides precise and flexible monitoring of load impedance or capacitance, improving the accuracy and precision of measurements even in the presence of noise, and supporting various electrostatic chuck configurations.
Implementation Method 1
the sinewave oscillator 16 generates a sinusoidal voltage at a predetermined frequency
Implementation Method 2
a current sensor adapted for generating a first alternating signal indicative of an oscillating current through the load, a voltage sensor adapted for generating a second alternating signal indicative of an oscillating voltage across the load
Implementation Method 3
An electrostatic chuck ('e-chuck') consists of a platen with surface electrodes which are biased with high voltage to set up an electrostatic force between the platen and the wafer
Implementation Method 4
A Coulomb chuck functions like a conventional dielectric capacitor
Implementation Method 5
The J-R type has a large but finite resistance, so current flows through it and the substrate when the surfaces are in close contact and voltage is applied. Charge accumulates at the interface between substrate and dielectric which provides the clamping force
Data Source
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AI summary
A power supply comprises a current sensor that measures an oscillating current through a load connected to the power supply, a voltage sensor that measures an oscillating voltage across the load, and a source conductor that transmits the sinusoidal voltage generated by a sinewave oscillator. A micro-controller is coupled to the current sensor, the voltage sensor, and the source conductor. The micro-controller computes the impedance or capacitance of the load by using digital data derived from the three sensors.