Adaptive Charge Neutralization With Ion Balance Feedback
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Solution Overview
Problem
Conventional charge neutralizers lack feedback mechanisms to accurately determine and adjust the balance of positive and negative ions for effective charge neutralization in semiconductor manufacturing, leading to potential inaccuracies in ion balance and increased swing voltages.
Innovation Solution
The implementation of an adaptive charge neutralization system that uses balance voltage feedback to modulate a high voltage, high frequency AC signal with a DC offset signal, adjusting the duty cycles to control the generation of positive and negative ions, thereby achieving a more accurate ion balance and reducing swing voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional charge neutralizers use predetermined ion balance without feedback, then device complexity is reduced, but manufacturing precision deteriorates due to inaccurate ion balance
Solution Approach 1:
The patent implements a feedback mechanism that measures the balance voltage between positive and negative ions and uses this measurement to dynamically adjust the ion generation. The control circuit continuously monitors the balance voltage and modifies the duty cycles of the AC signal applied to the ion emitter, creating a closed-loop system that automatically maintains accurate ion balance without requiring complex manual calibration
Solution Approach 2:
The charge neutralizer system performs self-adjustment by using its own output (ion balance) to control its operation. The balance voltage measurement from the system's ion output directly feeds back to the control circuit, which automatically adjusts the ion generation parameters. This self-regulating mechanism eliminates the need for external intervention or complex preset configurations
2Reliability
If conventional charge neutralizers lack adaptive control, then device complexity is reduced, but reliability deteriorates due to inability to maintain accurate ion balance under varying conditions
Solution Approach 1:
The patent transforms the static ion generation system into a dynamic one by continuously adjusting the duty cycles of the AC signal based on real-time balance voltage measurements. The system adapts to varying conditions (such as changes in air composition, temperature, or ion demand) by dynamically modifying its operation parameters, ensuring consistent ion balance reliability across different operating conditions
Solution Approach 2:
The control circuit changes the operational parameters (duty cycles of the AC signal) based on the measured balance voltage. When the balance voltage indicates an imbalance, the system adjusts the duty cycles to restore equilibrium. This parameter adjustment mechanism ensures reliable ion balance maintenance without requiring a complete system redesign
3Manufacturing precision
If conventional charge neutralizers use fixed duty cycles, then ease of operation is improved, but manufacturing precision deteriorates due to inability to control swing voltages
Solution Approach 1:
The feedback mechanism measures the balance voltage and uses this information to automatically adjust the duty cycles, eliminating the need for manual parameter tuning. The control circuit continuously optimizes the ion generation parameters to maintain swing voltages within the desired +/-5V range, achieving high precision without increasing operational complexity for the user
Solution Approach 2:
The system automatically adjusts its own parameters (duty cycles) based on real-time measurements of its performance (balance voltage). This self-adjusting capability reduces swing voltages to the precise +/-5V range without requiring the operator to manually calculate or set complex parameters, maintaining ease of operation while achieving high manufacturing precision
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 approach allows for precise control of ion balance within +/-5V, enhancing the accuracy and reducing voltage swing, which is beneficial for voltage-sensitive applications like semiconductor manufacturing.
Implementation Method 1
To generate gas ions, the amplitude of the applied voltage must be high enough to produce a corona discharge between at least two electrodes arranged as an ionization cell.
Implementation Method 2
disclosed example methods and apparatus for charge neutralization adapt an output ion balance based on balance voltage feedback. Example methods and apparatus for charge neutralization disclosed herein modulate a high voltage, high frequency AC signal using a DC offset signal to control generation of positive and negative ions.
Implementation Method 3
Ion emitters of charge neutralizers generate and supply both positive ions and negative ions into the surrounding air or gas media. To generate gas ions, the amplitude of the applied voltage must be high enough to produce a corona discharge between at least two electrodes arranged as an ionization cell.
Data Source
AI summary
An example apparatus for charge neutralization includes: a first emitter nozzle; a power supply configured to supply a high frequency alternating current (AC) signal to the first emitter nozzle; control circuitry configured to: provide a polarity signal to the power supply to generate a DC offset signal, wherein a combination of the high frequency AC signal and the DC offset signal causes the power supply to output a positive ion generation pulse or a negative ion generation pulse; control the polarity signal to cause the power supply to provide a period of positive ion generation and a period of negative ion generation; determine a balance voltage at an output of the first emitter nozzle; and control the polarity signal to adjust a relative durations of the period of positive ion generation and the period of negative ion generation based on the balance voltage.